Locating a mobile station and applications therefor

ABSTRACT

A location system is disclosed for wireless telecommunication infrastructures. The system is an end-to-end solution having one or more location systems for outputting requested locations of hand sets or mobile stations (MS) based on, e.g., AMPS, NAMPS, CDMA or TDMA communication standards, for processing both local mobile station location requests and more global mobile station location requests via, e.g., Internet communication between a distributed network of location systems. The system uses a plurality of mobile station locating technologies including those based on: (1) two-way TOA and TDOA; (2) home base stations and (3) distributed antenna provisioning. Further, the system can be modularly configured for use in location signaling environments ranging from urban, dense urban, suburban, rural, mountain to low traffic or isolated roadways. The system is useful for 911 emergency calls, tracking, routing, people and animal location including applications for confinement to and exclusion from certain areas.

RELATED APPLICATIONS

The present application is:

-   -   a continuation of U.S. application Ser. No. 09/820,584 filed        Mar. 28, 2001, and    -   a continuation-in-part of U.S. application Ser. No. 09/194,367        filed Nov. 24, 1998; U.S. application Ser. No. 09/820,584 is a        continuation of U.S. application Ser. No. 09/230,109 filed Jul.        8, 1999 (now U.S. Pat. No. 6,236,365) which is the National        Stage of International Application No. PCT/US97115933 filed Sep.        8, 1997 which, in turn, claims the benefit of the following        three applications: U.S. Provisional Application No. 60/056,603        filed Aug. 20, 1997, U.S. Provisional Application No. 60/044,821        filed Apr. 25, 1997; and U.S. Provisional Application No.        60/025,855 filed Sep. 9, 1996; U.S. application Ser. No.        09/194,367 is the National Stage of International Application        No. PCT/US97/15892, filed Sep. 8, 1997, which claims the benefit        of the following three provisionals: U.S. Provisional        Application No. 60/056,590 filed Aug. 20, 1997; U.S. Provisional        Application No. 60/044,821 filed Apr. 25, 1997; and U.S.        Provisional Application No. 60/025,855 filed Sep. 9, 1996. All        the above cited references are fully incorporated by reference        herein.

RELATED FIELD OF THE INVENTION

The present invention is directed generally to a system and method forlocating people or objects, and in particular to a system and method forlocating a wireless mobile radio station in a macro base station,distributed antenna, or home base station environment.

BACKGROUND OF THE INVENTION

Wireless communications systems are becoming increasingly importantworldwide. Wireless cellular telecommunications systems are rapidlyreplacing conventional wire-based telecommunications systems in manyapplications. Commercial mobile radio service provider networks, andspecialized mobile radio and mobile data radio networks are examples.The general principles of wireless cellular telephony have beendescribed variously, for example in U.S. Pat. No. 5,295,180 to Vendetti,et al filed April 8, 1992, which is incorporated herein by reference.There is great interest in using existing infrastructures for wirelesscommunication systems for locating people and/or objects in acost-effective manner. Such a capability would be invaluable in avariety of situations, especially in emergency or crime situations. Dueto the substantial benefits of such a location system, several attemptshave been made to design and implement such a system. Systems have beenproposed that rely upon signal strength and trilateralization techniquesto permit location include those disclosed in U.S. Pat. No. 4,818,998filed Mar. 31, 1986 and U.S. Pat. No. 4,908,629 filed Dec. 5, 1988 bothto Apsell et al. (“the Apsell patents”), and U.S. Pat. No. 4,891,650 toSheffer (“the Sheffer patent”) filed May 16, 1988. The Apsell patentsdisclose a system employing a “homing-in” scheme using radio signalstrength, wherein the scheme detects radio signal strength transmittedfrom an unknown location. This signal strength is detected by nearbytracking vehicles, such as police cruisers using receivers withdirectional antennas. Alternatively, the Sheffer patent discloses asystem using the FM analog cellular network. This system includes amobile transmitter located on a vehicle to be located. The transmittertransmits an alarm signal upon activation to detectors located at basestations of the cellular network. These detectors receive thetransmitted signal and transmit, to a central station, data indicatingthe signal strength of the received signal and the identity of the basestations receiving the signal. This data is processed to determine thedistance between the vehicle and each of the base stations and, throughtrilateralization, the vehicle's position. However, these systems havedrawbacks that include high expense in that special purpose electronicsare required. Furthermore, the systems are generally only effective inline-of-sight conditions, such as rural settings. Radio wave surfacereflections, refractions and ground clutter cause significantdistortion, in determining the location of a signal source in mostgeographical areas that are more than sparsely populated. Moreover,these drawbacks are particularly exacerbated in dense urban canyon(city) areas, where errors and/or conflicts in location measurements canresult in substantial inaccuracies.

Another example of a location system using time of arrival andtriangulation for location are satellite-based systems, such as themilitary and commercial versions of the Global Positioning Satellitesystem (GPS). GPS can provide accurate position determination (i.e.,about 100 meters error for the commercial version of GPS) from atime-based signal received simultaneously from at least threesatellites. A ground-based GPS receiver at or near the object to belocated determines the difference between the time at which eachsatellite transmits a time signal and the time at which the signal isreceived and, based on the time differentials, determines the object'slocation. However, the GPS is impractical in many applications. Thesignal power levels from the satellites are low and the GPS receiverrequires a clear, line-of-sight path to at least three satellites abovea horizon of about 60 degrees for effective operation. Accordingly,inclement weather conditions, such as clouds, terrain features, such ashills and trees, and buildings restrict the ability of the GPS receiverto determine its position. Furthermore, the initial GPS signal detectionprocess for a GPS receiver is relatively long (i.e., several minutes)for determining the receivers position. Such delays are unacceptable inmany applications such as, for example, emergency response and vehicletracking.

Differential GPS, or DGPS systems offer correction schemes to accountfor time synchronization drift. Such correction schemes include thetransmission of correction signals over a two-way radio link orbroadcast via FM radio station subcarriers. These systems have beenfound to be awkward and have met with limited success.

Additionally, GPS-based location systems have been attempted in whichthe received GPS signals are transmitted to a central data center forperforming location calculations. Such systems have also met withlimited success due, for example, to the limited reception of thesatellite signals and the added expense and complexity of theelectronics required for an inexpensive location mobile station orhandset for detecting and receiving the GPS signals from the satellites.

The behavior of a mobile radio signal in the general environment isunique and complicated. Efforts to perform correlation between radiosignals and distance between a base station and a mobile station aresimilarly complex. Repeated attempts to solve this problem in the pasthave been met with only marginal success. Factors include terrainundulations, fixed and variable clutter, atmospheric conditions,internal radio characteristics of cellular and PCS systems, such asfrequencies, antenna configurations, modulation schemes, diversitymethods, and the physical geometry of direct, refracted and reflectedwaves between the base stations and the mobile. Noise, such as man-madeexternally sources (e.g., auto ignitions) and radio system co-channeland adjacent channel interference also affect radio reception andrelated performance measurements, such as the analogcarrier-to-interference ratio (C/I), or digital energy-per-bit/Noisedensity ratio (E_(b/NO)) and are particular to various points in timeand space domains.

Before discussing real world correlation between signals and distance,it is useful to review the theoretical premise, that of radio energypath loss across a pure isotropic vacuum propagation channel, and itsdependencies within and among various communications channel types.

Over the last forty years various mathematical expressions have beendeveloped to assist the radio mobile cell designer in establishing theproper balance between base station capital investment and the qualityof the radio link, typically using radio energy field-strength, usuallymeasured in microvolts/meter, or decibels.

One consequence from a location perspective is that the effective rangeof values for higher exponents is an increased at higher frequencies,thus providing improved granularity of ranging correlation.

Actual data collected in real-world environments uncovered hugevariations with respect to the free space path loss equation, givingrise to the creation of many empirical formulas for radio signalcoverage prediction. Clutter, either fixed or stationary in geometricrelation to the propagation of the radio signals, causes a shadow effectof blocking that perturbs the free space loss effect. Perhaps the bestknown model set that characterizes the average path loss is Hata's,“Empirical Formula for Propagation Loss in Land Mobile Radio”, M. Hata,IEEE Transactions VT-29, pp. 317-325, August 1980, three pathlossmodels, based on Okumura's measurements in and around Tokyo, “FieldStrength and its Variability in VHF and UHF Land Mobile Service”, Y.Okumura, et al, Review of the Electrical Communications laboratory”, Vol16, pp 825-873, September-October 1968.

Although the Hata model was found to be useful for generalized RF waveprediction in frequencies under 1 GHz in certain suburban and ruralsettings, as either the frequency and/or clutter increased,predictability decreased. In current practice, however, fieldtechnicians often have to make a guess for dense urban an suburban areas(applying whatever model seems best), then installing a base stationsand begin taking manual measurements.

In 1991, U.S. Pat. No. 5,055,851 to Sheffer filed Nov. 29, 1989 taughtthat if three or more relationships have been established in atriangular space of three or more base stations (BSs) with a locationdatabase constructed having data related to possible mobile station (MS)locations, then arculation calculations may be performed, which usethree distinct P_(or) measurements to determine an X,Y, two dimensionallocation, which can then be projected onto an area map. Thetriangulation calculation is based on the fact that the approximatedistance of the mobile station (MS) from any base station (BS) cell canbe calculated based on the received signal strength. Shefferacknowledges that terrain variations affect accuracy, although as notedabove, Sheffer's disclosure does not account for a sufficient number ofvariables, such as fixed and variable location shadow fading, which aretypical in dense urban areas with moving traffic.

Most field research before about 1988 has focused on characterizing(with the objective of RF coverage prediction) the RF propagationchannel (i.e., electromagnetic radio waves) using a single-ray model,although standard fit errors in regressions proved dismal (e.g., 40-80dB). Later, multi-ray models were proposed, and much later, certainbehaviors were studied with radio and digital channels. In 1981, Voglerproposed that radio waves at higher frequencies could be modeled usingoptics principles. In 1988 Walfisch and Bertoni applied optical methodsto develop a two-ray model, which when compared to certain highlyspecific, controlled field data, provided extremely good regression fitstandard errors of within 1.2 dB.

In the Bertoni two ray model it was assumed that most cities wouldconsist of a core of high-rise buildings surrounded by a much largerarea having buildings of uniform height spread over regions comprisingmany square blocks, with street grids organizing buildings into rowsthat are nearly parallel. Rays penetrating buildings then emanatingoutside a building were neglected.

After a lengthy analysis it was concluded that path loss was a functionof three factors: 1.) the path loss between antennas in free space; 2.)the reduction of rooftop wave fields due to settling; and 3.) the effectof diffraction of the rooftop fields down to ground level.

However, a substantial difficulty with the two-ray model in practice isthat it requires a substantial amount of data regarding buildingdimensions, geometry, street widths, antenna gain characteristics forevery possible ray path, etc. Additionally, it requires an inordinateamount of computational resources and such a model is not easily updatedor maintained.

Unfortunately, in practice clutter geometry and building heights arerandom. Moreover, data of sufficient detail is extremely difficult toacquire, and regression standard fit errors are poor; i.e., in thegeneral case, these errors were found to be 40-60 dB. Thus the two-raymodel approach, although sometimes providing an improvement over singleray techniques, still did not predict RF signal characteristics in thegeneral case to level of accuracy desired (<10 dB).

Work by Greenstein has since developed from the perspective ofmeasurement-based regression models, as opposed to the previous approachof predicting-first, then performing measurement comparisons. Apparentlyyielding to the fact that low-power, low antenna (e.g., 12-25 feet aboveground) height PCS microcell coverage was insufficient in urbanbuildings, Greenstein, et al, authored “Performance Evaluations forUrban Line-of-sight Microcells Using a Multi-ray Propagation Model”, inIEEE Globecom Proceedings, December 1991. This paper proposed the ideaof formulating regressions based on field measurements using small PCSmicrocells in a lineal microcell geometry (i.e., geometries in whichthere is always a line-of-sight path between a subscriber's mobile andits current microsite). Additionally, Greenstein studied thecommunication channels variable Bit-Error-Rate (BER) in a spatialdomain, which was a departure from previous research that limited fieldmeasurements to the RF propagation channel signal strength alone.However, Greenstein based his finding on two suspicious assumptions: 1)he assumed that distance correlation estimates were identical for uplinkand downlink transmission paths; and 2) modulation techniques would betransparent in terms of improved distance correlation conclusions.Although some data held very correlation, other data and environmentsproduced poor results. Accordingly, his results appear unreliable foruse in general location context.

In 1993 Greenstein, et al, authored “A Measurement-Based Model forPredicting Coverage Areas of Urban Microcells”, in the IEEE Journal OnSelected Areas in Communications, Vol. 11, No. 7, September 1993.Greenstein reported a generic measurement-based model of RF attenuationin terms of constant-value contours surrounding a given low-power, lowantenna microcell environment in a dense, rectilinear neighborhood, suchas New York City. However, these contours were for the cellularfrequency band. In this case, LOS and non-LOS clutter were consideredfor a given microcell site. A result of this analysis was that RFpropagation losses (or attenuation), when cell antenna heights wererelatively low, provided attenuation contours resembling a spline planecurve depicted as an asteroid, aligned with major street grid patterns.Further, Greenstein found that convex diamond-shaped RF propagation losscontours were a common occurrence in field measurements in a rectilinearurban area. The special plane curve asteroid is represented by theformula:

x^(2/3)+y^(2/3)=r^(2/3). However, these results alone have not beensufficiently robust and general to accurately locate an mobile station,due to the variable nature of urban clutter spatial arrangements.

At Telesis Technology in 1994 Howard Xia, et al, authored “MicrocellularPropagation Characteristics for Personal Communications in Urban andSuburban Environments”, in IEEE Transactions of Vehicular Technology,Vol. 43, No. 3, August 1994, which performed measurements specificallyin the PCS 1.8 to 1.9 GHz frequency band. Xia found corresponding butmore variable outcome results in San Francisco, Oakland (urban) and theSunset and Mission Districts (suburban).

The physical radio propagation channel perturbs signal strength,frequency (causing rate changes, phase delay, signal to noise ratios(e.g., C/I for the analog case, or E_(b/No), RF energy per bit, overaverage noise density ratio for the digital case) and Doppler-shift.Signal strength is usually characterized by:

Free Space Path Loss (L_(p))

Slow fading loss or margin (L_(slow))

Fast fading loss or margin (L_(fast))

The cell designer increases the transmitted power P_(TX) by the shadowfading margin L_(slow) which is usually chosen to be within the 1-2percentile of the slow fading probability density function (PDF) tominimize the probability of unsatisfactorily low received power levelP_(RX) at the receiver. The PRX level must have enough signal to noiseenergy level (e.g., 10 dB) to overcome the receiver's internal noiselevel (e.g., −118 dBm in the case of cellular 0.9 GHz), for a minimumvoice quality standard. Thus in this example P_(RX) must never be below−108 dBm, in order to maintain the quality standard.

Additionally the short term fast signal fading due to multipathpropagation is taken into account by deploying fast fading marginL_(fast), which is typically also chosen to be a few percentiles of thefast fading distribution. The 1 to 2 percentiles compliment othernetwork blockage guidelines. For example the cell base station trafficloading capacity and network transport facilities are usually designedfor a 1-2 percentile blockage factor as well. However, in the worst-casescenario both fading margins are simultaneously exceeded, thus causing afading margin overload.

In Roy Steele's, text, Mobile Radio Communications, IEEE Press, 1992,estimates for a GSM system operating in the 1.8 GHz band with atransmitter antenna height of 6.4 m and a mobile station receiverantenna height of 2 m, and assumptions regarding total path loss,transmitter power would be calculated as follows: TABLE 1 GSM PowerBudget Example Parameter dBm value Will require L_(slow) 14 L_(fast) 7LI_(path) 110 Min. RX pwr required −104 TXpwr = 27 dBm

Steele's sample size in a specific urban London area of 80,000 LOSmeasurements and data reduction found a slow fading variance ofσ=7 dBassuming log-normal slow fading PDF and allowing for a 1.4% slow fadingmargin overload, thusL_(slow)=2σ=14 dBThe fast fading margin was determined to be:L_(fast)=7 dB

In contrast, Xia's measurements in urban and suburban California at 1.8GHz uncovered flat-land shadow fades on the order of 25-30 dB when themobile station (MS) receiver was traveling from LOS to non-LOSgeometries. In hilly terrain fades of +5 to −50 dB were experienced.Thus it is evident that attempts to correlate signal strength withmobile station ranging distance suggest that error ranges could not beexpected to improve below 14 dB, with a-high side of 25 to 50 dB. Basedon 20 to 40 dB per decade, Corresponding error ranges for the distancevariable would then be on the order of 900 feet to several thousandfeet, depending upon the particular environmental topology and thetransmitter and receiver geometries.

Although the acceptance of fuzzy logic has been generally more rapid innon-American countries, the principles of fuzzy logic can be applied inwireless location. Lotfi A. Zadeh's article, “Fuzzy Sets” published in1965 in Information and Control, vol. 8, Pg 338-353, herein incorporatedby reference, established the basic principles of fuzzy logic, amongwhich a key theorem, the FAT theorem, suggests that a fuzzy system witha finite set of rules can uniformly approximate any continuous (orBorel-measureable) system. The system has a graph or curve in the spaceof all combinations of system inputs and outputs. Each fuzzy ruledefines a patch in this space. The more uncertain the rule, the widerthe patch. A finite number of small patches can always cover the curve.The fuzzy system averages patches that overlap. The Fat theorem wasproven by Bart Kosko, in a paper entitled, “Fuzzy Systems as UniversalApproximators”, in Proceedings of the First IEEE Conference on FuzzySystems, Pages 1153-1162, in San Diego, on March, 1992, hereinincorporated by reference.

Fuzzy relations map elements of one universe, say “X”, to those ofanother universe, say “Y”, through the Cartesian product of the twouniverses. However, the “strength” of the relation between ordered pairsof the two universes is not measured with the characteristic function(in which an element is either definitely related to another element asindicated by a strength value of “1”, or is definitely not related toanother element as indicated by a strength value of “0”, but rather witha membership function expressing various “degrees” of strength of therelation on the unit interval [0,1]. Hence, a fuzzy relation R is amapping from the Cartesian space X×Y to the interval [0,1], where thestrength of the mapping is expressed by the membership function of therelation for ordered pairs from the two universes or μ_(R)(x,y).

Just as for crisp relations, the properties of commutativity,associativity, distributivity, involution and idempotency all hold forfuzzy relations. Moreover, DeMorgan's laws hold for fuzzy relations justas they do for crisp (classical) relations, and the null relations O,and the complete relation, E, are analogous to the null set and thewhole set in set-theoretic from, respectively. The properties that donot hold for fuzzy relations, as is the case for fuzzy sets in general,are the excluded middle laws. Since a fuzzy relation R is also a fuzzyset, there is overlap between a relation and its complement, hence.R∪R′≠ER∩R′≠O

As seen in the foregoing expression, the excluded middle laws forrelation do not result in the null relation, O, or the completerelation, E. Because fuzzy relations in general are fuzzy sets, theCartesian product can be defined as a relations between two or morefuzzy sets. Let A be a fuzzy set on universe X and B be a fuzzy set onuniverse Y; then the Cartesian product between fuzzy sets A and B willresult in a fuzzy relation R, which is contained within the fullCartesian product space, orA×B=R⊂X×Y

where the fuzzy relation R has membership function:μ_(R)(x,y)=μ_(A×B)(x,y)=min(μ_(A)(x),μ_(B)(y))

Fuzzy composition can be defined just as it is for crisp (binary)relations. If R is a fuzzy relation on the Cartesian space X×Y, and S isa fuzzy relation on the Cartesian space Y×Z, and T is a fuzzy relationon the Cartesian space X×Z; then fuzzy max-min composition is defined interms of the set-theoretic notation and membership function-theoreticnotation in the following manner:μ_(T)(x,y)=

(μ_(R)(x,y)

μ_(S)(x,y))=max {min [μ_(R)(x,y), μ_(S)(y,z)]}

The fuzzy extension principle allows for transforms or mappings of fuzzyconcepts in the form y=f(x). This principle, combined with acompositional rule of inference, allows for a crisp input to be mappedthrough a fuzzy transform using membership functions into a crispoutput. Additionally, in mapping a variable x into a variable y, both xand y can be vector quantities.

SUMMARY OF THE INVENTION OBJECTS OF THE INVENTION

It is an objective of the present invention to provide a system andmethod for determining wireless location using one or more commercialmobile radio telecommunication systems for accurately locating peopleand/or objects in a cost effective manner. Related objectives for thepresent invention include providing a system and method that:

(1) can be readily incorporated into existing commercial wirelesstelephony systems with few, if any, modifications of a typical telephonywireless infrastructure;

(2) can use the native electronics of typical commercially availabletelephony wireless mobile stations (e.g., handsets) as location devices;

(3) can be used for locating people and/or objects residing indoors.

Yet another objective is to provide a low cost location system andmethod, adaptable to wireless telephony systems, for usingsimultaneously a plurality of base stations owned and/or operated bycompeting commercial mobile radio service providers within a commonradio coverage area, in order to achieve FCC phase 2 or other accuracyrequirements, and for synergistically increasing mobile station locationaccuracy and consistency.

Yet another objective is to provide a low cost location system andmethod, adaptable to wireless telephony systems, for using a pluralityof location techniques In particular, at least some of the followingmobile station location techniques can be utilized by variousembodiments of the present invention:

(4.1) time-of-arrival wireless signal processing techniques;

(4.2) time-difference-of-arrival wireless signal processing techniques;

(4.3) adaptive wireless signal processing techniques having, forexample, learning capabilities and including, for instance, neural netand genetic algorithm processing;

(4.4) signal processing techniques for matching MS location signals withwireless signal characteristics of known areas;

(4.5) conflict resolution techniques for resolving conflicts inhypotheses for MS location estimates;

(4.6) enhancement of MS location estimates through the use of bothheuristics and historical data associating MS wireless signalcharacteristics with known locations and/or environmental conditions.

Yet another objective is to provide a system and method for flexibledelivery of location information to Public Safety Answering Points, endusers, centralized dispatchers, as well as to agents (either human ormechanized) associated with trigger-based inventory and trackingsystems. Flexible delivery used here indicates providing location viavarious two dimensional closed-form shapes, such as polygons, ellipses,etc., which bound the location probabilities. In cases where heightlocation information is known, the bounding shape may bethree-dimensional.

Yet another objective is to provide a system and method for a variety ofnew location-based services for public and private group safety,including family support functions.

Yet another objective is to provide a system and method for NationalScale Wireless Location capability. Although the primary focus of thispatent is to provide wireless location with accuracy to meet the FCCphase two requirements, a system and method is provided that alsoutilizes roaming signaling to determine in which city is a particularwireless mobile station located.

Yet another objective is to provide and system and method forParametric-driven, intelligent agent-based location services. Parametersmay include time, location, and user-specific and/or group specificcriteria.

Yet another objective is to provide a system and method for determiningand/or enhancing wireless location using one or more of the following:(a.) CDMA-based Distributed Antenna technology; (b.) Home Base Stationsand AIN technology.

Yet another objective is to provide notification messages and/orvoice-synthesized call or text paging function to a plurality of othermobile station users when a mobile station user travels into, or awayfrom, one or more zones or are within short distances of shopping malls,stores, merchandising dealers etc.

Yet another objective is to provide notification messages and/orvoice-synthesized call or text paging functions to a plurality of othermobile station users when a mobile station dials a redefined telephonenumber, such as 911, or a type of “mild emergency cry for help” number.

Yet another objective is to provide notification messages and/orvoice-synthesized call or text paging function to a plurality of othermobile station users when a mobile station user dials a predefinedtelephone number, such as 311, or a type of mild emergency cry for helpnumber, wherein the plurality of other mobile station users are within aparticular distance, or a minimum distance to the mobile station userwho dialed the predefined number.

Yet another objective is to provide notification messages and/orvoice-synthesized call or text paging function to a plurality of othermobile station users when a mobile station user dials a predefinedtelephone number, such as 311, or a type of mild emergency cry for helpnumber, wherein the plurality of other mobile station users are within aparticular distance, or a minimum distance to the mobile station userwho dialed the predefined number, and wherein the other mobile stationusers are provided individualized directional or navigation informationfrom their current locations, to reach to the mobile station user whodialed the predefined number.

Yet another objective is to provide automatic home office, vehicle andboat security functions, which are activated and deactivated based on amobile station user's location to or away from a location associatedwith the security functions.

Yet another objective is to provide notifications (e.g., via fax, page,e-mail, text paging or voice synthesized call message), or to setup agroup conference call capability to a plurality of predefinedindividuals, based on a mobile station user's call to 911, or based on amobile station user's traveling into or away from a location zone orarea, or based upon a sensor input signal to the user's mobile station,such as a sudden change in G forces, such as falling down, having thecar hit another object suddenly, air bag deployment, etc.

Yet another objective is to provide location information to a ‘searcher’mobile station user who then further refines or narrows the scope of thelocation/search for a ‘target’ mobile station, or the mobile station tobe located, using a small microwave dish, in communication with, or tosupplement/replace the searcher mobile station antenna, whose physicalorientation is used to further determine the target mobile stationlocation, relative to the searcher's mobile stationposition/orientation.

Yet another objective is to provide a means to allow more flexiblestorage, inventory and enhanced user accessibility of rental vehicles,by combining location technology of rental car driver carrying his/herown mobile station, along with a mobile station which remains alwaysactive and fixed to a rental car. By maintaining accurate locationrecords of rental car locations and automatic, remote-control of rentalcars (or smart cars) which use the mobile station to telemeter controldata to and from the car, whose doors, door locks, and generalaccessibility are controlled by a centralized computer system, rentalcars can be dropped off at convenient shopping center malls, airportparking lots, hotels and at other convenient locations.

Yet another objective is to provide location estimates to users carryingmobile stations, via voice synthesis, data circuit messaging or textpaging.

Yet another objective is to provide a mechanism whereby mobile stationusers may access and control their subscriber profile for locationpurposes. The location subscriber profile is a persistent data storewhich contains logic regarding under what criteria will that mobilestation user allow his/her location to be made known, and to whom. Themobile station user may access the location profile via several methods,including Internet means, and mobile station handset keypad entry andvoice recognition circuits.

Yet another objective is to utilize signaling detection characteristicsof other CDMA base stations and systems in a given area, owned andoperated by an another commercial mobile radio service provider (CMRSprovider). By including other CMRS providers' infrastructure in thelocation estimation analysis process, improvements in location accuracycan be realized.

DEFINITIONS

The following definitions are provided for convenience. In general, thedefinitions here are also defined elsewhere in this document as well.

-   (1) The term wireless herein is, in general, an abbreviation for    digital wireless, and in particular, wireless refers to digital    radio signaling using one of standard digital protocols such as    CDMA, TDMA and GSM, as one skilled in the art will understand.-   (2) As used herein, the term mobile station (equivalently, MS)    refers to a wireless device that is at least a transmitting device,    and in most cases is also a wireless receiving device, such as a    portable radio telephony handset. Note that in some contexts herein    instead or in addition to mobile station, the following terms are    also used: personal station (PS), and location unit (LU). In    general, these terms may be considered synonymous. However, the    later two terms may be used when referring to reduced functionality    communication devices in comparison to a typical digital wireless    mobile telephone.-   (3) The term, infrastructure, denotes the network of telephony    communication services, and more particularly, that portion of such    a network that receives and processes wireless communications with    wireless mobile stations. In particular, this infrastructure    includes telephony wireless base stations (BS) such as those for    radio mobile communication systems based on CDMA, TDMA, and GSM    wherein the base stations provide a network of cooperative    communication channels with an air interface with the mobile    station, and a conventional telecommunications interface with a    Mobile Switch Center (MSC). Thus, an MS user within an area serviced    by the base stations may be provided with wireless communication    throughout the area by user transparent communication transfers    (i.e., hand-offs) between the user's mobile station and these base    stations in order to maintain effective telephony service. The    mobile switch center provides communications and control    connectivity among base stations and the public telephone network.-   (4) An example of a Parametric-driven intelligent agent-based    location service follows: An intelligent agent software process    monitors sets of Parametric conditions and location scenarios. When    appropriate conditions and location criteria are satisfied, then a    set of notifications or other actions are triggered to occur. A    specific example follows: given that a certain child carrying a    mobile station should be in a certain school between 8:00 A.M. and    3:00 P.M. on regular school days, then a wireless location request    is invoked periodically, within the school day time frame. If a    location request determines that the child's mobile station is    located substantially outside of the general school area, then a    parent/guardian is notified of that fact, and of the child's    location via any of several methods, such as: (a.) a    voice-synthesized telephone message, (b.) various extranet/internet    means, such as electronic mail, netcasting, such as the product    Castanet, by Marimba Software, Inc., (c.) fax to a pre-determined    telephone number, or (d.) alpha-numeric text paging.-   (5) Commercial mobile radio service (CMRS) service provider is the    referenced name of the company that owns and/or operates a publicly    accessible wireless system in the cellular or PCS spectrum radio    bands.-   (6) The term “geolocation” as used herein refers to “a    representation of at least one of: a geographical location or a    geographical extent”. Thus, the term “GeoLocation Message” refers to    a message that contains a content representative of at least one of:    a geographical location or a geographical extent. Moreover, the term    “geolocation result” refers to a result that represents at least one    of: a geographical location or a geographical extent, and the term    “geolocation related processing” is intended to mean “processing    that is related to a result that represents at least one of: a    geographical location or a geographical extent”.

SUMMARY DISCUSSION

The location system of the present invention accomplishes the above andother objectives by the following steps:

(1.) receiving signal data measurements corresponding to wirelesscommunications between a mobile station to be located (herein alsodenoted the target mobile station) and a wireless telephonyinfrastructure, wherein the mobile station, MS and/or mobile switchcenter may be enhanced in certain novel and cost effective ways so as toprovide an extended number of values characterizing the wireless signalcommunications between the target mobile station and the base stationinfrastructure, such infrastructure including multiple, distinct CMRSwhere base stations share a common coverage area;

(2.) organizing and processing the signal data measurements receivedfrom a given target mobile station and surrounding base stations so thatcomposite wireless signal characteristic values may be obtained fromwhich target mobile station location estimates may be derived. Inparticular, the signal data measurements are ensembles of samples fromthe wireless signals received from the target mobile station by the basestation infrastructure, and from associated base stations wherein thesesamples are subsequently filtered using analog and digital spectralfiltering.

(3.) providing the resultant location estimation characteristic valuesto a mobile station location estimate model, wherein each such model(also denoted a “first order model” or FOM) subsequently determines theestimate of the location of the target mobile station based on, forexample, the signal processing techniques (1.) through (2.) above.

Accordingly, steps (1.) and (2.) above are performed by a subsystem ofthe invention denoted the Signal Processing and Filtering Subsystem (orsimply the Signal Processing Subsystem). In particular, this subsystemreceives samples of wireless signal characteristic measurements such asa plurality of relative signal strengths and corresponding signal timedelay value pairs, wherein such samples are used by this subsystem toproduce the component with the least amount of multipath, as evidencedin the sample by the short time delay value, wherein each such valuepair is associated with wireless signal transmissions between the targetmobile station and a particular base station of a predetermined wirelessbase station infrastructure. Extremely transient signal anomalies suchas signal reflection from tree leaves or the passing of a truck arelikely to be filtered out by the Signal Processing Subsystem. Forexample, such an ensemble of data value pairs can be subjected to inputcropping and various median filters employing filtering techniques suchas convolution, median digital, Fast Fourier transform, Radon transform,Gabar transform, nearest neighbor, histogram equalization, input andoutput cropping, Sobel, Wiener, and the like.

It is a further aspect of the present invention that the wirelesspersonal communication system (PCS) infrastructures currently beingdeveloped by telecommunication providers offer an appropriate localizedinfrastructure base upon which to build various personal locationsystems employing the present invention and/or utilizing the techniquesdisclosed herein. In particular, the present invention is especiallysuitable for the location of people and/or objects using code divisionmultiple access (CDMA) wireless infrastructures, although other wirelessinfrastructures, such as, time division multiple access (TDMA)infrastructures and GSM are also contemplated. Note that CDMA personalcommunications systems are described in the Telephone IndustriesAssociation standard IS-95, for frequencies below 1 GHz, and in theWideband Spread—Spectrum Digital Cellular System Dual-Mode MobileStation-Base Station Compatibility Standard, for frequencies in the1.8-1.9 GHz frequency bands, both of which are incorporated herein byreference. Furthermore, CDMA general principles have also beendescribed, for example, in U.S. Pat. No. 5,109,390, to Gilhousen, et alfiled Nov. 7, 1989, and CDMA Network Engineering Handbook by Qualcomm,Inc., each of which is also incorporated herein by reference.

In another aspect of the present invention, in environments where a homebase station capability exists, then wireless location can be providedunder certain circumstances, wherein when a mobile station user iswithin a predetermined range of, for example, 1000 feet of his/herpremises, the user's mobile station is detected through mobile stationreceiving electronics provided in, for example, cordless telephone unitsas being at home. Thus, the local public telephone switching network maybe provided with such information for registering that user is at home,and therefore the mobile station may be allowed to function as acordless home telephone utilizing the local public telephone switchingnetwork instead of the base station infrastructure. According to thisaspect of the present invention, the location center of the presentinvention receives notification from the local public switched telephonenetwork that the mobile station is at or near home and utilizes thisnotification in outputting a location estimate for the mobile station.

For example, in one embodiment, the present invention includes low cost,low power base stations, denoted location base stations (LBS) above,providing, for example, CDMA pilot channels to a very limited area abouteach such LBS. The location base stations may provide limited voicetraffic capabilities, but each is capable of gathering sufficientwireless signal characteristics from an MS within the location basestation's range to facilitate locating the MS. Thus, by positioning thelocation base stations at known locations in a geographic region suchas, for instance, on street lamp poles and road signs, additional MSlocation accuracy can be obtained. That is, due to the low power signaloutput by such location base stations, for there to be communicationbetween a location base station and a target MS, the MS must berelatively near the location base station. Additionally, for eachlocation base station not in communication with the target MS, it islikely that the MS is not near to this location base station. Thus, byutilizing information received from both location base stations incommunication with the target MS and those that are not in communicationwith the target MS, the present invention can substantially narrow thepossible geographic areas within which the target MS is likely to be.Further, by providing each location base station (LBS) with a co-locatedstationary wireless transceiver (denoted a built-in MS above) havingsimilar functionality to an MS, the following advantages are provided:

(4.1) assuming that the co-located base station capabilities and thestationary transceiver of an LBS are such that the base stationcapabilities and the stationary transceiver communicate with oneanother, the stationary transceiver can be signaled by anothercomponent(s) of the present invention to activate or deactivate itsassociated base station capability, thereby conserving power for the LBSthat operate on a restricted power such as solar electrical power;

(4.2) the stationary transceiver of an LBS can be used for transferringtarget MS location information obtained by the LBS to a conventionaltelephony base station;

(4.3) since the location of each LBS is known and can be used inlocation processing, the present invention is able to (re)train and/or(re)calibrate itself in geographical areas having such LBSs. That is, byactivating each LBS stationary transceiver so that there is signalcommunication between the stationary transceiver and surrounding basestations within range, wireless signal characteristic values for thelocation of the stationary transceiver are obtained for each such basestation.

In yet another aspect, the present invention includes a capability forlocating a target mobile station within areas of poor reception forinfrastructure base stations by utilizing distributed antennas. Adistributed antenna system as used herein is a collection of antennasattached in series to a reduced function base station, wherein theantennas are distributed throughout an area for improving telephonycoverage. Such distributed antenna systems are typically used in indoorenvironments (e.g., high rise buildings) or other areas wherein thesignal to noise ratio is too high for adequate communication withstandard infrastructure base stations. Also a distributed antenna systemmay be located such that its coverage pattern overlaps the area ofcoverage of another distributed antenna system. In such cases each ofthe overlapping distributed antenna systems includes purposeful delayelements to provide different signal delays for each of the overlappingantenna systems and thereby provide multipath signals with sufficientdelay spread for signal discrimination, as one skilled in the art willunderstand. Accordingly, the present invention receives and utilizeslocation information communicated from distributed antenna systems forlocating a target mobile station. That is, the present invention mayreceive information from the base station infrastructure indicating thata target mobile station is communicating with such a distributed antennasystem and provide distributed antenna signal characteristic valuesrelated to the distributed antenna system. Accordingly, to process suchtarget mobile station location signal data, the present inventionincludes a distributed antenna system for generating target mobilestation location estimate derived from the location signal data obtainedfrom the distributed antenna system.

The location system of the present invention offers many advantages overexisting location systems. The system of the present invention, forexample, is readily adaptable to existing wireless communication systemsand can accurately locate people and/or objects in a cost-effectivemanner. In particular, the present invention requires few, if any,modifications to commercial wireless communication systems forimplementation. Thus, existing personal communication systeminfrastructure base stations and other components of, for example,commercial CDMA infrastructures are readily adapted to the presentinvention. The present invention can be used to locate people and/orobjects that are not in the line-of-sight of a wireless receiver ortransmitter, can reduce the detrimental effects of multipath on theaccuracy of the location estimate, can locate people and/or objectslocated indoors as well as outdoors, and uses a number of wirelessstationary transceivers for location. The present invention employs anumber of distinctly different location computational models (FOMs) forlocation which provides a greater degree of accuracy, robustness andversatility than is possible with existing systems. For instance, thelocation models provided include not only the radius-radius/TOA and TDOAtechniques but also adaptive neural net techniques. Further, the presentinvention is able to adapt to the topography of an area in whichlocation service is desired. The present invention is also able to adaptto environmental changes substantially as frequently as desired. Thus,the present invention is able to take into account changes in thelocation topography over time without extensive manual datamanipulation.

Moreover, there are numerous additional advantages of the system of thepresent invention when applied in CDMA communication systems. Thelocation system of the present invention readily benefits from thedistinct advantages of the CDMA spread spectrum scheme, namely theexploitation of radio frequency spectral efficiency and isolation by (a)monitoring voice activity, (b) management of two-way power control, (c)provision of advanced variable-rate modems and error correcting signalencoding, (d) inherent resistance to fading, (e) enhanced privacy, and(f) multiple “rake” digital data receivers and searcher receivers forcorrelation of signal multipaths.

Additionally, note that this architecture need not have all modulesco-located. In particular, it is an additional aspect of the presentinvention that various modules can be remotely located from one anotherand communicate with one another via telecommunication transmissionssuch as telephony technologies and/or the Internet. Accordingly, thepresent invention is particularly adaptable to such distributedcomputing environments. For example, some number of the location centermodules may reside in remote locations and communicate their generatedhypotheses of mobile station location estimates (each such hypothesisalso denoted a “location hypothesis” herein) via the Internet.

In an alternative embodiment of the present invention, the processingfollowing the generation of location estimates by the modules may besuch that this processing can be provided on Internet user nodes and themodules may reside at Internet server sites. In this configuration, anInternet user may request hypotheses from such remote modules andperform the remaining processing at his/her node.

Additionally, note that it is within the scope of the present inventionto provide one or more central location development sites that may benetworked to, for example, dispersed location centers or systemsproviding location services according to the present invention, whereinthe modules may be accessed, substituted, enhanced or removeddynamically via network connections with a central location developmentsite. Thus, a small but rapidly growing municipality in substantiallyflat low density area might initially be provided with access to, forexample, two or three modules for generating location hypotheses in themunicipality's relatively uncluttered radio signaling environment.However, as the population density increases and the radio signalingenvironment becomes cluttered by, for example, thermal noise andmultipath, additional or alternative modules may be transferred via thenetwork to the location center for the municipality.

Of course, other software architectures may also to used in implementingthe processing of the location center without departing from scope ofthe present invention. In particular, object-oriented architectures arealso within the scope of the present invention. For example, the modulesmay be object methods on an mobile station location estimator object,wherein the estimator object receives substantially all target mobilestation location signal data output by the signal filtering subsystem20. Alternatively, software bus architectures are contemplated by thepresent invention, as one skilled in the art will understand, whereinthe software architecture may be modular and facilitate parallelprocessing.

One embodiment of the present invention includes providing the locationof a mobile station (MS) using the digital air interface voice channeland an automatic call distributor device. This embodiment provideslocation information to either the initiating caller who wishes to learnof his location, using the voice channel, and/or location informationcould be provided to another individual who has either a wireline orwireless telephone station.

Another embodiment of the present invention includes providing thelocation of a mobile station using the digital air interface voicechannel and a hunt group provided from a central office or similardevice. This embodiment provides location information to either theinitiating caller who wishes to learn of his location, using the voicechannel, and/or location information could be provided to anotherindividual who has either a wireline or wireless telephone station.

Another embodiment of the present invention includes providing thelocation of a mobile station using the digital air interface textpaging, or short message service channel and a hunt group provided froma central office or similar device. This embodiment provides locationinformation to either the initiating caller who wishes to learn of hislocation, using the voice channel, and/or location information could beprovided to another individual who has either a wireline or wirelesstelephone station.

Another embodiment of the present invention includes providing thelocation of a plurality of mobile stations using the public Internet oran intranet, with either having the ability to further use “push”, or“netcasting” technology. This embodiment provides location informationto either the initiating Internet or Intranet user who wishes to learnof one or more mobile station locations, using either the Internet or anintranet. Either the mobile station user to be located can initiate arequest for the user to be located, or an Internet/intranet user mayinitiate the location request. Optionally the location information couldbe provided autonomously, or periodically, or in accordance with otherlogic criteria, to the recipient of the location information via theInternet or a intranet. As a further option, location information can besuperimposed onto various maps (e.g., bit/raster, vector, digitalphotograph, etc.) for convenient display to the user.

Yet another embodiment of the present invention includes providing amulticast notification to a group of mobile station users, based ondistress call from a particular mobile station, wherein the group ofmobile station users are relatively nearby the distress caller. Themulticast notification provides individual directions for each groupmobile station user, to direct each user to the fastest route to reachthe distressed caller.

Other aspects of the present invention can be described as follows:

Aspect 1. An apparatus for locating a first mobile station for at leasttransmitting and receiving radio signals, wherein said radio signals arereceived on a forward radio bandwidth and said radio signals aretransmitted on a different reverse radio bandwidth, comprising:

-   -   a first wireless network infrastructure for communicating with        said first mobile station, said first wireless network        infrastructure having:        -   (A1) a plurality of spaced apart base stations for            communicating via said radio signals with said first mobile            station, and        -   (A2) a mobile switching center for communicating with said            first mobile station, via said radio signals with the base            stations, wherein said mobile switching center also            communicates with said plurality of base stations for            receiving measurements of said radio signals, said            measurements including: (i) first measurements of said radio            signals received by said first mobile station in said            forward radio bandwidth, and (ii) second measurements of            said radio signals transmitted by said first mobile station            in said reverse radio bandwidth;    -   a location determining means for locating said first mobile        station, wherein said location determining means receives said        first and second measurements from the mobile switching center        for estimating a location of said first mobile station, wherein        said estimate is a function of both said first measurements and        said second measurements.

Aspect 2. An apparatus for locating a mobile station as in Aspect 1,further including an interface means between said location determiningmeans and said mobile switching center, wherein said interface meansgenerates a location request for a primary one of said base stations towhich said first mobile signaling means is in communication.

Aspect 3. An apparatus for locating a mobile station as in Aspect 1,further including a means for requesting data related to additionalradio signals between said first mobile station and at least a secondwireless network infrastructure different from said first wirelessnetwork infrastructure.

Aspect 4. An apparatus for locating a mobile station as in Aspect 1,wherein said first wireless network infrastructure is capable ofcommunicating at least one of voice and visual information with saidfirst mobile station.

Aspect 5. An apparatus for locating a mobile station, comprising:

-   -   a wireless network infrastructure for communicating with a        plurality of mobile stations, each said mobile station for        transmitting and receiving wireless signals, wherein said        wireless signals are received in a forward bandwidth and said        wireless signals are transmitted in a different reverse        bandwidth, and, said wireless network infrastructure having a        plurality of spaced apart base stations for communicating via        said wireless signals with said plurality of mobile stations;    -   a location determining means for communicating with said        plurality of mobile stations, via said radio signals with the        base stations, wherein said location determining means        communicates with said plurality of base stations for receiving        measurements related to said radio signals for estimating a        location of at least a first of said plurality of mobile        stations, said measurements including: (i) first measurements of        said wireless signals received by said first mobile station in        said forward radio bandwidth, and (ii) second measurements of        said wireless signals transmitted by said first mobile station        in said reverse radio bandwidth;    -   wherein said location determining means estimates a location of        said first mobile station using both said first measurements and        said second measurements.

Aspect 6. An apparatus for locating a mobile station as in Aspect 5,wherein said second measurements are determined from said wirelesssignals being received by said base stations.

Aspect 7. An apparatus for locating a mobile station as in Aspect 5,wherein said measurements include at least one of: a delay spread, asignal strength, a ratio of energy per bit versus signal to noise, aword error rate, a frame error rate, a mobile signaling means, a powercontrol value, a pilot index, a finger identification, an arrival time,an identification of said first mobile station for communicating withthe wireless network infrastructure, a make of said first mobilestation, a revision of said first mobile station, a sectoridentification of one of the base stations receiving said radio signalstransmitted from said first mobile station.

Aspect 8. An apparatus for locating a mobile station as in Aspect 5,wherein said radio signals are communicated using one of: CDMA, W-CDMA,TDMA and advanced mobile phone service.

Aspect 9. An apparatus for locating a mobile station as in Aspect 5,wherein said location determining means includes a location estimatorusing time difference of arrival data from said measurements.

Aspect 10. An apparatus for locating a mobile station as in Aspect 9,wherein said location estimator receives said measurements from adistributed antenna system.

Aspect 11. An apparatus for locating a mobile station as in Aspect 9,wherein said location estimator receives active, candidate and remainingset information from said first mobile signaling means.

Aspect 12. An apparatus for locating a mobile station as in Aspect 1,wherein said location determining means includes:

-   -   a receiving means for receiving first data related to at least        one of said first measurements and said second measurements        between said first mobile station and said wireless network        infrastructure;    -   activating a first location estimator for outputting a first        estimate of a location of said first mobile station when        supplied with location information from said receiving means,        said location information related to the first data;    -   outputting said first estimate of the location of said first        mobile station when said first estimate has an extent less than        or equal to a predetermined size;    -   activating a second location estimator for outputting a second        estimate of a location of said first mobile station when said        first location estimator does not provide said first estimate        having an extent less than or equal to a predetermined size;    -   outputting an estimate of the location of said first mobile        station when said second location estimator provides said second        estimate.

Aspect 13. A method for locating a wireless mobile station, comprising:transmitting, by a first short range transceiver station, a statuschange related to whether the mobile station and said first short rangetransceiver station are able to wirelessly communicate through atelephony network to a predetermined storage; storing, in saidpredetermined storage, said status of a mobile station, wherein saidstatus has a first value when the mobile station communicates with saidshort range transceiver station as a cordless telephone, and said statushas a second value when the mobile station communicates with a networkof base stations, wherein said base stations are cooperatively linkedfor providing wireless communication; detecting, by said first shortrange transceiver station, a change accessing said predetermined storagefor determining a location of the mobile station.

Aspect 14. A method for locating a wireless mobile station, as in Aspect13, wherein said short range transceiver is a home base station.

Aspect 15. A method for locating a wireless mobile station, as in Aspect13, wherein said predetermined storage is accessible via one of: anautonomous notification message and a request-response message.

Aspect 16. A method for locating a wireless mobile station, as in Aspect13, wherein said predetermined storage is a home location register.

Aspect 17. A method for locating a wireless mobile station, as in Aspect13, wherein said predetermined storage includes one or more of thefollowing data items related to said mobile station: mobile stationidentification number, short range transceiver identification and mobileswitch center identification.

Aspect 18. A method for locating a wireless mobile station, as in Aspect13, wherein said step of accessing includes responding to a query ofsaid predetermined storage location using an identification of themobile station.

Aspect 19. A method for locating a wireless mobile station, as in Aspect13, further including providing said status from said predeterminedstorage together with an identification of the mobile station to amobile station location estimator for estimating a location of themobile station.

Aspect 20. A method for location a wireless mobile station, as in Aspect17, wherein said step of transmitting further includes associating saidchange with a predetermined fixed location and said short rangetransceiver identification.

Aspect 21. A method for location a wireless mobile station, as in Aspect13, wherein said step of accessing includes translating the mobileidentification number and said short range transceiver identificationinto a predetermined location when the status has said firstpredetermined value.

Aspect 22. A method for location a wireless mobile station, as in Aspect13, further including a prior step of provisioning a translatingdatabase from a customer care system containing the location of theshort range transceiver.

Aspect 23. A method for locating a wireless mobile station, comprising:receiving data of wireless signals communicated between a mobile stationand a wireless network; detecting, using said first data, that themobile station is in wireless communication with a distributed antennasystem having a plurality of antennas connected in series anddistributed along a signal conducting line so that there is apredetermined signal time delay between said antennas and atpredetermined locations; determining a plurality of signal time delaymeasurements for signals transmitted between the mobile station and acollection of some of said antennas, wherein said signals are alsocommunicated through said line; estimating a location of the mobilestation using said plurality of signal time delay measurements.

Aspect 24. A method for locating a wireless mobile station as in Aspect23, wherein said step of estimating includes correlating eachmeasurement of said plurality of signal time delay measurements with aunique corresponding one of said antennas.

Aspect 25. A method for locating a wireless mobile station as in Aspect24, wherein said step of estimating includes: identifying a plurality ofantennas in said collection using correlation obtained in said step ofcorrelating; determining a corresponding signal time delay between themobile station and each antenna in said collection; determining alocation of each antenna in said collection; estimating a location ofthe mobile station using said corresponding signal time delays and saidlocations of each antenna in said collection.

Aspect 26. A method for locating a wireless mobile station as in Aspect23, wherein said step of estimating includes determining, for saidsignal time delay measurements, a common signal time delay correspondingto transmitting signals from said distributed antenna system to areceiver of the first wireless network.

Aspect 27. A method for locating a wireless mobile station as in Aspect23, wherein said step of estimating includes using an absolute delaytime with respect to a pilot channel for a base station on the wirelessnetwork.

Aspect 28. A method for locating a wireless mobile station as in Aspect23, wherein said step of estimating includes performing a triangulationusing values related to one of: a signal time of arrival, and a signaltime difference of arrival for time difference of arrival correspondingto each antenna in said collection.

Aspect 29. A method for locating a wireless mobile station, as in Aspect23 wherein said step of estimating includes a step of computing a mostlikely location of said mobile station using a fuzzy logic computation.

Aspect 30. A method for locating a wireless mobile station as in Aspect23, wherein said step of activating includes activating one of:

-   -   (a) a location estimator for determining whether the mobile        station is detected by a base station of the network, wherein        said base station communicates with the mobile station as a        cordless telephone;    -   (b) a location estimator for estimating a location of the mobile        station using location information obtained from said        distributed antenna system;    -   (c) a location estimator for estimating a location of the mobile        station by one of: triangulation and trilateration.

Aspect 31. A method for locating a wireless mobile station, comprising:first receiving first signal characteristic measurements of wirelesssignals communicated between a mobile station and a first network ofbase stations, wherein said base stations in the first network arecooperatively linked by a first wireless service provider for providingwireless communication; instructing the mobile station to search for awireless signal from a second network of base stations that arecooperatively linked by a second wireless service provider for providingwireless communication, wherein said first and second wireless serviceproviders are different; second receiving second signal characteristicmeasurements of wireless signals communicated between the mobile stationand said second network of base stations; estimating a location of themobile station using said first and second signal characteristicmeasurements.

Aspect 32. A method for locating a wireless mobile station as in Aspect31, wherein the mobile station is registered for a wirelesscommunication service with the first wireless service provider, and themobile station is not registered for the wireless communication servicewith the second wireless service provider.

Aspect 33. A method for locating a wireless mobile station as in Aspect31, wherein said step of instructing includes transmitting a command tothe mobile station for instructing the mobile station to search for asignal from a base station of said second wireless service provider in afrequency bandwidth different from a frequency bandwidth forcommunicating with the base stations of said first wireless serviceprovider.

Aspect 34. A method for locating a wireless mobile station as in Aspect31, wherein said step of instructing includes transmitting a command tothe mobile station for instructing the mobile station to hand-off fromsaid first service provider to a base station associated with saidsecond service provider, for purposes of performing additional signalmeasurements.

Aspect 35. A method for locating a wireless mobile station as in Aspect31, wherein said first signal characteristic measurements includemeasurements for time delay, signal strength pairs of signalcommunicated from at least one of:

-   -   (a) the base stations of said first network to the mobile        station, and    -   (b) the mobile station to the base stations of said first        network, and    -   wherein said second signal characteristic measurements include        measurements for time delay, signal strength pairs of signals        communicated from the base stations of said second network to        the mobile station.

Aspect 36. A method for locating a wireless mobile station, comprising:receiving first data related to wireless signals communicated between amobile station and at least a first network of a plurality of commercialmobile service provider networks of base stations, wherein for each saidnetwork, there is a plurality of base stations for at least one oftransmitting and receiving wireless signals with a plurality of mobilestations; instructing the mobile station to communicate with a secondnetwork of the plurality of networks for supplying second data;activating a mobile station location estimator, when said first andsecond data are obtained for providing an estimate of a location of themobile station.

Aspect 37. A method for locating a wireless mobile station, as in Aspect36, wherein said second network includes a second plurality of basestations, wherein a majority of base stations in said second pluralityof base stations has a location different from the locations of basestations in said first network.

Aspect 38. A method for locating a wireless mobile station, as in Aspect36, wherein at least one of said first and second data includes signalcharacteristic measurements of communication with the mobile station fora time interval of less than 10 seconds.

Aspect 39. A method for locating a wireless mobile station, comprising:first receiving first signal characteristic measurements of wirelesssignals communicated between a mobile station and a first network ofbase stations, wherein said base stations in the first network arecooperatively linked by a first wireless service provider for providingwireless communication; instructing a second network of base stationsthat are cooperatively linked by a second wireless service provider forproviding wireless communication so that the second network searches forwireless signals from the mobile station, wherein said first and secondwireless service providers are different; second receiving second signalcharacteristic measurements of wireless signals communicated between themobile station and said second network of base stations; estimating alocation of the mobile station using said first and second signalcharacteristic measurements.

Aspect 40. A method for locating a wireless mobile station, as in Aspect39, further including a step of requesting the mobile station to raiseit's transmitter power level to a predetermined level, prior to saidstep of instructing.

Aspect 41. A method for locating a wireless mobile station, comprising:receiving, by a receiving means, first data related to wireless signalscommunicated between a mobile station and at least a first network of aplurality of commercial mobile service provider networks, wherein foreach said network, there are a plurality of communication stations forat least one of transmitting and receiving wireless signals with aplurality of mobile stations; first activating a location estimator forproviding a first estimate of a location of the mobile station whensupplied with first location information from said receiving means, saidfirst location information related to the first data;

-   -   when one of: (a) said first estimate does not exist, and (b)        said first estimate has an extent greater than or equal to a        predetermined size, the steps (A1) and (A2) are performed:    -   (A1) instructing the mobile station to communicate with a second        network of the plurality of networks for supplying second data        to said receiving means, wherein said second data is related to        wireless signals communicated between the mobile station and the        second network;

(A2) second activating said location estimator a second time forproviding a second estimate of a location of the mobile station whensupplied with additional location information from said receiving means,said additional location information related to the second data;

-   -   outputting at least one of the estimates of the location of the        mobile station provided by said location estimator when said        location estimator provides at least one estimate of the        location of the mobile station.

Aspect 42. A method for locating a wireless mobile station as in Aspect41, wherein said additional location information and said first locationinformation are utilized together by said location estimator.

Aspect 43. A method of locating a wireless mobile station as in Aspect41, wherein said communication stations include wireless base stationsfor one of CDMA, TDMA, and GSM.

Aspect 44. A method of locating a wireless mobile station as in Aspect43, wherein said communication stations include home base stations.

Aspect 45. A method of locating a wireless mobile station as in Aspect41, wherein the mobile station includes one of: a CDMA transmitter, aTDMA transmitter, and a GSM transmitter, and a AMPS transmitter.

Aspect 46. A method for locating a wireless mobile station as in Aspect41, wherein one or more of said activating steps includes:

-   -   (a) said location estimator for determining whether the mobile        station is detected by a communication station which        communicates with the mobile station as a cordless telephone;    -   (b) said location estimator for estimating a location of the        mobile station using location information related to data from a        distributed antenna system;    -   (c) said location estimator for estimating a location of the        mobile station by one of: triangulation and trilateration.

Aspect 47. A method for locating a wireless mobile station as in Aspect41, wherein said predetermined extent is less than one thousand feet.

Aspect 48. A method for locating a wireless mobile station, comprising:receiving, by a receiving means, first data related to wireless signalscommunicated between a mobile station and at least a first network ofone or more commercial mobile service provider networks, wherein foreach said network, there is a different plurality of base stations forat least one of transmitting and receiving wireless signals with aplurality of mobile stations; activating a first location estimator foroutputting a first estimate of a location of the mobile station whensupplied with location information from said receiving means, saidlocation information related to the first data; outputting said firstestimate of the location of the mobile station when said first estimatehas an extent less than or equal to a predetermined size; activating asecond location estimator for outputting a second estimate of a locationof the mobile station when said first location estimator does notprovide said first estimate having an extent less than or equal to apredetermined size; outputting an estimate of the location of the mobilestation when said second location estimator provides said secondestimate.

Aspect 49. A method for locating a wireless mobile station as in Aspect48 further including a step of instructing the mobile station tocommunicate with a second network of the plurality of networks forsupplying second data to said receiving means, wherein said second datais related to wireless signals communicated between the mobile stationand the second network.

Aspect 50. A method for locating a wireless mobile station as in Aspect49, wherein said step of instructing includes a step of instructing themobile station to hand-off to said second network for synchronizingtiming signals and performing measurements between the mobile station ansaid second network.

Aspect 51. A method for locating a wireless mobile station as in Aspect48, wherein one or more of said activating steps includes activating oneof:

-   -   (a) a location estimator for determining whether the mobile        station is detected by one of the base stations which        communicates with the mobile station as a cordless telephone;    -   (b) a location estimator for estimating a location of the mobile        station using location information related to data from a        distributed antenna system;    -   (c) a location estimator for estimating a location of the mobile        station by one of: triangulation and trilateration.

Aspect 52. A method for locating a mobile station, comprising:receiving, by said mobile station, a request control message from one ofa plurality of base stations, wherein said message is received by areceiving antenna of said mobile station; the control message providinginformation related to said message to at least one of a controlprocessor and a searcher receiver in said mobile station; determining,using at least one of said control processor and said searcher receiver,a plurality of pairs of radio signal strength related values andcorresponding signal time delays for a wireless communication betweensaid mobile station and at least a first of the base stations, whereinfor at least some of said pairs, said signal time delays are different,and for each pair, said signal strength related value for said pair isobtained using a signal strength of said communication at saidcorresponding signal time delay of said pair; transmitting signals forsaid pairs to one or more of the base stations via a transmittingantenna of said mobile station; routing data for at least one of saidpairs from said one or more base stations to a mobile station locationestimator for estimating a location of said mobile station.

Aspect 53. A method for locating a mobile station, as in Aspect 52,wherein said step of receiving uses one of a CDMA, an AMPS, a NAMPS anda TDMA wireless standard.

Aspect 54. A method for locating a mobile station, as in Aspect 52,wherein said step of determining is performed for a wirelesscommunication between said mobile station and each of a plurality of thebase stations.

Aspect 55. A method for locating a mobile station, as in Aspect 52,wherein each of said signal time delays is included within apredetermined corresponding time delay spread.

Aspect 56. A method for locating a mobile station, as in Aspect 52,wherein said step of determining includes a step of instructing, by saidcontrol processor, said searcher receiver to output a plurality of saidradio signal strength related values for a plurality of fingersresulting from said communication from said first base station to saidmobile station.

Aspect 57. A method for locating a mobile station, as in Aspect 52,wherein said step of determining includes inputting data for said pairsto a modulator for modulating said data prior to said step oftransmitting.

Aspect 58. A method for locating a mobile station, as in Aspect 57,further including a step of establishing a software controllable dataconnection between said control processor and a mobile station componentincluding at least one of: a user digital baseband component and saidmodulator, wherein said connection inputs said data to said component.

Aspect 59. A method for locating a mobile station, as in Aspect 52further including a step of providing said data for said pairs to amobile station location estimating system having a first mobile stationlocation estimating component using time difference of arrivalmeasurements for locating said mobile station via one of trilaterationand triangulation.

Aspect 60. A method for locating a mobile station, as in Aspect 59,wherein said step of providing includes selecting one of: said firstmobile station estimating component, a second mobile station estimatingcomponent using data obtained from a distributed antenna system, and athird mobile station estimating component for using data obtained fromactivation of a home base station.

Aspect 61. A method for locating a mobile station, as in Aspect 60,further including a step of computing a most likely location of saidmobile station using a fuzzy logic computation.

Aspect 62. A method for locating a mobile station, as in Aspect 61,wherein said step of computing is performed by said second mobilestation estimating component for determining a most likely floor thatsaid mobile station resides in a multi-story building having adistributed antenna system.

Aspect 63. A method for locating a mobile station, as in Aspect 59,further including a step of requesting data for additional pairs ofradio signal strength related values and corresponding signal timedelays for a wireless communication between said mobile station and atleast a second base station of a commercial mobile radio serviceprovider different from a commercial mobile service provider for saidfirst base station.

Aspect 64. A method for obtaining data related to wireless signalcharacteristics, comprising: providing a user with a mobile station foruse when the user traverses a route having one or more predeterminedroute locations, wherein one or more of the route locations have acorresponding telephone number and a corresponding description stored inthe mobile station; performing the following substeps when the uservisits each of the route locations: activating a call to saidcorresponding telephone number; transmitting a code identifying theroute location when the user is substantially at the route location;storing an association of:

-   -   (a) signal characteristic measurements for wireless        communication between the mobile station and one or more base        stations, and    -   (b) a unique identifier for the route location obtained using        said code transmitted by said call;    -   Wherein said stored signal characteristic measurements are        accessible using said unique identifier.

Aspect 65. A method as in Aspect 64, wherein said unique identifiercorresponds to one of: (a) an address for the route location, and (b) alatitude and longitude of the route location.

Aspect 66. A method as in Aspect 64, wherein said route is periodicallytraversed by a user having a mobile station for accomplishing said stepof performing.

Aspect 67. A method as in Aspect 64, wherein said step of storingincludes retaining said signal characteristic measurements in a datastorage for analyzing signal characteristic measurements of wirelesscommunications between mobile stations and a wireless infrastructure ofbase stations.

Aspect 68. A method as in Aspect 64, further including, prior to saidstep of activating, a step of determining, by the user, that a displayon the mobile station uniquely identifies that said correspondingdescription of the route location is available for calling saidcorresponding telephone number and transmitting said identifying code.

Aspect 69. A method as in Aspect 64, wherein said step of storingincludes: obtaining a phone number identifying the mobile station;providing said phone number identifying the mobile station to acommercial mobile radio service provider in a request for said signalcharacteristic measurements.

Aspect 70. A method as in Aspect 64, wherein said step of storingincludes using a phone number identifying the mobile station incombination with said transmitted identifying code for determining saidunique identifier.

Aspect 71. A method as in Aspect 64, wherein said correspondingdescription includes at least one of: a textual description of itscorresponding route location, and an address of its corresponding routelocation.

Aspect 72. A method as in Aspect 64, further including steps of:associating said identifying code for the route location and said uniqueidentifier in a data storage prior to performing said step ofperforming; accessing said data storage using said identifying code forobtaining said unique identifier in said step of storing.

Aspect 73. A method as in Aspect 64, further including a step ofaccessing said stored signal characteristic measurements for enhancing aperformance of a process for locating mobile stations.

Aspect 74. A method as in Aspect 64, wherein at least two of said one ormore base stations are in networks of different commercial mobile radioservice providers.

Aspect 75. A method as in Aspect 64, further including a step offiltering said signal characteristic measurements so that when saidsignal characteristic measurements are suspected of being transmittedfrom a location substantially different from the route location, saidstep of storing is one of: (a) not performed, and (b) performed so as toindicate that said signal characteristic measurements are suspect.

Aspect 76. A method as in Aspect 75, wherein said step of filteringincludes at least one of: (a) determining an amount by which anestimated location of the mobile station using said signalcharacteristic measurements differs from a location of the mobilestation obtained from said unique identifier; (b) determining whether apredetermined amount of time has elapsed between successive performancesof said step of activating.

Aspect 77. A method for locating a wireless mobile station, comprising:

-   -   first receiving first signal characteristic measurements of        wireless signals communicated between a mobile station and a        first network of base stations, wherein said first signal        characteristic measurements includes:        -   (a) one or more pairs of wireless signal strength related            values and corresponding signal time delays for a wireless            communication between the mobile station and at least a            first of the base stations;        -   (b) data identifying operational characteristics of the            mobile station including information related to a signal            transmission power for the mobile station and information            for determining a maximum transmission power level of the            mobile station;    -   adjusting, for at least one of said pairs, its corresponding        wireless signal strength, using said data, thereby obtaining        corresponding adjusted pairs, wherein each adjusted pair has the        corresponding adjusted signal strength, and wherein said        adjusted signal strength is an expected signal strength of a        predetermined standardized mobile station transmitter power        level having a predetermined maximum transmission power and        operating at a predetermined transmission power level;    -   outputting second signal characteristic information, obtained        using said adjusted signal strength, to a mobile station        location estimator for determining a location estimate of said        first mobile station.

Aspect 78. A method for locating a mobile station as in Aspect 77,further including applying sequence of one or more signal processingfilters to one of: said pairs and said adjusted pairs.

Aspect 79. A method for locating a mobile station as in Aspect 78,wherein said sequence of filters is dependent upon a correspondingmobile station location estimator.

Aspect 80. A method for locating a mobile station as in Aspect 79,wherein said sequence of filters is pipelined so that for first andsecond filters of said sequence, an output of said first filter is aninput to said second filter.

Aspect 81. A method for locating a mobile station as in Aspect 79,wherein said filters include Sobel, Weiner, median and neighbor.

Aspect 82. A method for locating a wireless mobile station, comprising:

-   -   first receiving first signal characteristic measurements of        wireless signals communicated between a mobile station and a        first network of base stations, wherein said first signal        characteristic measurements includes one or more pairs of        wireless signal strength related values and corresponding signal        time delays for a wireless communication between the mobile        station and at least a first of the base stations;    -   categorizing said pairs into categories according to ranges of        signal strength related values and ranges of corresponding        signal time delays for obtaining a representation of a frequency        of occurrence of said one or more pairs in said categories;    -   applying one or more filters to said representation for one        of: (a) reducing characteristics of said representation that are        expected to be insufficiently repeatable for use in identifying        a location of the mobile station, and (b) enhancing a signal to        noise ratio;    -   supplying an output obtained from said step of applying to a        mobile station location estimator;    -   estimating a location of the mobile station using said mobile        station location estimator.

Aspect 83. A method for locating a wireless mobile station as in Aspect82, further including a step of requesting data for additional pairs ofwireless signal strength related values and corresponding signal timedelays for a wireless transmission between the mobile station and atleast a second base station of a second network of base stationsdifferent from the base stations of the first network, wherein saidfirst and second networks communicate with the mobile station indifferent signal bandwidths.

Aspect 84. A method for locating a wireless mobile station as in Aspect83, wherein the first network is operated by a first commercial mobileradio service provider and the second network is operated by a secondcommercial mobile radio service provider.

Aspect 85. A method for locating a wireless mobile station as in Aspect82, wherein said representation corresponds to a histogram.

Aspect 86. A method for locating a wireless mobile station as in Aspect82, further including a step of normalizing one of: (a) said pairs, and(b) values corresponding to said output.

Aspect 87. A method for locating a wireless mobile station as in Aspect23, wherein said step of activating further includes the step ofapplying a fuzzy logic module which further discretizes the locationestimate provided from one of:

-   -   (a) a location estimator for estimating a location of the mobile        station using location information obtained from said        distributed antenna system;    -   (b) a location estimator for estimating a location of the mobile        station by one of: triangulation and trilateration.

Aspect 88. A method for contacting a telephony station, comprising:associating, by a user, a particular telephony number with a collectionof one or more telephony station numbers of telephony stations withwhich the user desires to communicate when said particular telephony,number is called from a predetermined telephony station; receiving saidparticular telephony number from the predetermined telephony station;

-   -   determining a location of said predetermined telephony station        and at least some of said telephony stations having telephony        station numbers in said collection; selecting a first of said        telephony stations having telephony station numbers in said        collection, wherein said first telephony station is selected        according to a location of said predetermined telephony station        and a location of first telephony station;    -   transmitting a user desired message to said first telephony        station.

Aspect 89. A method for locating a mobile station, comprising:establishing, by a user of a particular mobile station, a collection ofidentities of one or more persons having permission to receive alocation of said particular mobile station; receiving a request by afirst of said persons for locating said particular mobile station;determining a location of said particular mobile station in response tosaid request, said location determined using measurements of wirelesstransmissions between said particular mobile station and a firstwireless network of base stations, wherein said base stations arecooperatively linked for wireless communication; outputting saidlocation to the first person.

Aspect 90. A method as in Aspect 89, wherein said step of determiningincludes using measurements of wireless transmissions between saidparticular mobile station and a second wireless network of base stationsprovided by a different commercial wireless service provider from acommercial wireless service provider for the first wireless network.

Aspect 91. An apparatus for locating a mobile station as in Aspect 3,further including a means for providing a location estimate using theInternet.

Aspect 92. An apparatus for locating a mobile station as in Aspect 3,further including a means for providing a location estimate usingdigital certificate keys and the Internet.

Aspect 93. An apparatus for locating a mobile station as in Aspect 91,further including a means for providing a location estimate using pushtechnology on the Internet.

Further description of the advantages, benefits and patentable aspectsof the present invention will become evident from the accompanyingdrawings and description hereinbelow. All novel aspects of theinvention, whether mentioned explicitly in this Summary section or not,are considered subject matter for patent protection either singly or incombination with other aspects of the invention. Accordingly, such novelaspects of the present invention disclosed hereinbelow and/or in thedrawings that may be omitted from, or less than fully described in, thisSummary section are fully incorporated herein by reference into thisSummary. In particular, all claims of the Claims section hereinbelow arefully incorporated herein by reference into this Summary section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an overall view of a wireless location system andmethod for using multiple commercial mobile radio service providers;

FIG. 2 shows is a high level wireless location architecture using theintelligent network, which illustrates aspects of the home base stationand Internet connectivity for receiving location requests and forproviding location estimates;

FIG. 3 illustrates how the signals from the base stations associatedwith various multiple commercial radio service providers can be sharedwith the wireless location system to provide an improved geometry andthus improved wireless location accuracy.

FIG. 4 shows how the mobile station database in the location system isupdated via interfaces in communication with multiple commercial mobileradio service providers using customer care systems.

FIG. 5 shows a method of direct access to multiple CMRS base stations,from the location system perspective, thus avoiding the need tosignificantly modify network infrastructure systems.

FIG. 6 illustrates physical components and the effects of predeterminedsignal delay, and total system delay in a distributed antennaenvironment for purposes of wireless location;

FIG. 7 shows the timing relationships among the signals within adistributed antenna system.

FIG. 8 shows a flowchart of the methods and procedures required toimplement a DA database;

FIG. 9 illustrates an exemplary DA configuration with a direct antennaconnection to the base stations;

FIG. 10 illustrates an alternative DA configuration using multipointmicrowave;

FIG. 11 illustrates how multiple base stations could be used via amicrowave circuit to provide PCS and location service to a multilevelbuilding via virtual pilot channels;

FIG. 12 shows the DA delay spread ranges possible for a 500 microsecondguard zone;

FIG. 13 shows DA-cell layout a geometry and how location geometries canbe constructed;

FIG. 14 illustrates the realization of actual measurements andclassification utilized within DA cell ranges to determine a percentrange within each cell.

FIG. 15 shows the standard components of a CDMA MS.

FIG. 16 shows one embodiment for MS modification that facilitiesenhanced RF measurement telemetry.

FIG. 17 shows how the LC is used in a Home Base Station architecture.

FIG. 18 illustrates a typical case where signals from three basestations can be detected.

FIG. 19 illustrates a typical case where signals from four base stations(including remaining set information) can be detected.

FIG. 20 shows a MS detection scheme with a two base station geometry.

FIG. 21 illustrates a typical amorphous location area with only thesignal detection of a single base station sector, by a MS.

FIG. 22 shows a series of typical reverse path CDMA RF measurements in adense urban area.

FIG. 23 shows a series of typical reverse path CDMA RF measurements in arural setting.

FIG. 24 shows a typical Location Center connection to a CTIA Model.

FIG. 25 shows a typical national Location Center and relevant networkconnections.

FIG. 26 illustrates a typical three dimensional delay spread profile.

FIG. 27 shows the magnifying effects of convoluting similar-propertyforward and reverse path three-dimensional images.

FIG. 28 illustrates an image and relief representation of a CDMA DelaySpread Profile.

FIG. 29 illustrates the main components of the Signal ProcessingSubsystem 20.

FIG. 30 illustrates an image based on an RF signal measurement sampleset, before image histogram equalization filtering is applied.

FIG. 31 illustrates an image based on an RF signal measurement sampleset, after image histogram equalization input cropping filtering isapplied.

FIG. 32 illustrates an image sample grid before image filtering.

FIG. 33 shows a CDMA profile image after input cropping is used at alevel of 50 percent.

FIG. 34 illustrates the results of combining input cropping at 40percent, then performing four by four median filtering on the resultant.

FIG. 35 shows the results of combining input cropping at 50 percent withfour by four median filtering.

FIG. 36 illustrates how location estimates can be provided using voicechannel connections via an ACD and Internet technology.

FIG. 37 shows wireless Location of a MS using the Voice Channel from aHunt Group.

FIG. 38 illustrates how location information can be provided via Textpaging or short message service messaging.

FIG. 39 shows how location information of an MS can be provided viaInternet via “Push” technology.

FIG. 40 illustrates how location directions can be provided to nearestmembers, regarding directions for each individual member to reach adistressed MS caller.

FIG. 41 illustrates how traveling instructions from two different pointscan be provided to an initiator.

FIG. 42 illustrates how wireless location services can be used tofacilitate automotive rental car tracking and control.

FIG. 43 indicates the addition of a fuzzy logic module which discretizesthe wireless location estimate output from the TOA/TDOA locationestimator module.

DETAILED DESCRIPTION

Various digital wireless communication standards have been introducedsuch as code division multiple access (CDMA) and Time Division MultipleAccess (TDMA) (e.g., Global Systems Mobile (GSM). These standardsprovide numerous enhancements for advancing the quality andcommunication capacity for wireless applications. Referring to CDMA,this standard is described in the Telephone Industries Associationstandard IS-95, for frequencies below 1 GHz, and in J-STD-008, theWideband Spread-Spectrum Digital Cellular System Dual-Mode MobileStation-Base station Compatibility Standard, for frequencies in the1.8-1.9 GHz frequency bands.

Additionally, CDMA general principles have been described, for example,in U.S. Pat. No. 5,109,390, Diversity Receiver in a CDMA CellularTelephone System, by Gilhousen, et al, filed Nov. 7, 1989. There arenumerous advantages of such digital wireless technologies such as CDMAradio technology. For example, the CDMA spread spectrum scheme exploitsradio frequency spectral efficiency and isolation by monitoring voiceactivity, managing two-way power control, provision of advancedvariable-rate modems and error correcting signal design, and includesinherent resistance to fading, enhanced privacy, and provides formultiple “rake” digital data receivers and searcher receivers forcorrelation of multiple physical propagation paths, resembling maximumlikelihood detection, as well as support for multiple base stationcommunication with a mobile station, i.e., soft or softer hand-offcapability. When coupled with a location center as described herein,substantial improvements in radio location can be achieved. For example,the CDMA spread spectrum scheme exploits radio frequency spectralefficiency and isolation by monitoring voice activity, managing two-waypower control, provision of advanced variable-rate modems and errorcorrecting signal design, and includes inherent resistance to fading,enhanced privacy, and provides for multiple “rake” digital datareceivers and searcher receivers for correlation of multiple physicalpropagation paths, resembling maximum likelihood detection, as well assupport for multiple base station communication with a mobile station,i.e., soft hand-off capability. Moreover, this same advanced radiocommunication infrastructure can also be used for enhanced radiolocation. As a further example, the capabilities of IS-41 and AINalready provide a broad-granularity of wireless location, as isnecessary to, for example, properly direct a terminating call to amobile station. Such information, originally intended for callprocessing usage, can be re-used in conjunction with the location centerdescribed herein to provide wireless location in the large (i.e., todetermine which country, state and city a particular mobile station islocated) and wireless location in the small (i.e., which location, plusor minus a few hundred feet within one or more base stations a givenmobile station is located).

FIG. 1 illustrates a wireless location network using two commercialmobile radio service provider networks for the present invention.Accordingly, this figure illustrates the interconnections between thecomponents of a typical wireless network configuration and variouscomponents that are specific to the present invention. In particular, asone skilled in the art will understand, a typical wireless networkincludes: (a) a mobile switching center (MSC) 112 a; (b) generally aservice control point 4 a, and base stations (not shown) which are incommunication with a mobile switch center 112 a. Within a typicalmetropolitan area it is also common for a second commercial mobile radioservice (CMRS) provider to offer wireless service within essentiallysimilar coverage areas, such systems typically including an mobileswitch center 112 b, service control point 4 b, and associated basestations (not shown). Added to this wireless network, the presentinvention provides the following additional components:

(1) a location system or center 142 which is required for determining alocation of a target mobile station using signal characteristic valuesas measured by the target mobile station (not shown) and nearby basestations (not shown), further including of the following modules orsubsystem components:

(1.1) an application programming interface 14 (having a controller alsodenoted by the label “14”), for physically interfacing with andcontrolling the messaging to and from each CMRS mobile switch center 112a, 112 b, service control points 4 a and 4 b, receiving locationrequests from either the mobile switch center 112 a, or 112 b, or theInternet 468, and providing connection to the signal processingsubsystem 20;

(1.2) a signal processing subsystem 20, which is in communication withthe application programming interface (L-API) 14. The signal processor20 receives, queues, filters and processes signal measurement messagesinto various formats suitable for the location estimate modules DA 10and TOA/TDOA 8;

(1.3) a TOA/TDOA location estimate module 8, in communication with thesignal processing subsystem 20. The TOA/TDOA module 8 provides alocation estimate result, using a time of arrival or a time differenceof arrival technique based on conditioned signals from the signalprocessing subsystem 20; in addition the TOA/TDOA module may alsoprocess signals from the distributed antenna module 10, in order toprovide a location estimate within environments containing distributedantenna systems;

(1.4) a distributed antenna (DA) module 10, which receives signalsrelated to distributed antennas, from the signal processor 20 incommunication a location estimating capability for utilizing one or moredistributed antenna systems 168 as shown in FIG. 2, wherein each suchsystem 168 provides wireless location information for an MS 140 withinthe area in communication with one or more distributed antenna system168.

(1.5) a home base station module (HBS) 6 in FIG. 1, which receivessignals from the (application programming interface) controller 14 anddetermines wireless location (i.e., providing a location estimateresult) based on registration principles of the wireless user's mobilestation when in communication with the user's home base station (notshown) in communications with a given service control point 4 a or 4 b,containing a home base station application (not shown).

Since home base stations and distributed antenna systems can be locatedon potentially each floor of a multi-story building, in such cases whereinfrastructure is installed, the wireless location technology describedherein can be used to perform location in terms of height as well as byLatitude and Longitude.

Referring to FIG. 2, additional detail is provided of typical basestation coverage areas, sectorization, and high level components used inthe present invention's scope, including the mobile switch center 112, amobile station 140 in communication with a home base station 160, andcommunication between the location system 142 and the public Internet468, via an Internet service provider interface 472. A novel aspect ofthis invention includes providing wireless location estimate informationto various designated users via the public Internet. Although basestations may be placed in any configuration, a typical deploymentconfiguration is approximately in a cellular honeycomb pattern, althoughmany practical tradeoffs exist, such as site availability, versus therequirement for maximal terrain coverage area. To illustrate, suchexemplary base stations (BSs) 122 a through 122 g are shown, each ofwhich radiate referencing signals within their area of coverage tofacilitate mobile station (MS) 140 radio frequency connectivity, andvarious timing and synchronization functions. A given base station maycontain no sectors (not shown), thus radiating and receiving signals ina 360 degree omnidirectional coverage area pattern, or the base stationmay contain “smart antennas” (not shown) which have specialized coveragearea patterns.

Alternatively and generally most frequent are base stations having threesector coverage area patterns. Shown in FIG. 2, each sector for basestation 122 a through 122 g contains three sectors, labeled a, b, and c,which represent antennas that radiate and receive signals in anapproximate 120 degree arc, from an overhead view. As one skilled in theart will understand, actual base station coverage areas generally aredesigned to overlap to some extent, thus ensuring seamless coverage in ageographical area. Control electronics within each base station are usedto communicate with a given mobile station 140. Further, duringcommunication with the mobile station the exact base stationidentification and sector identification information are known and areprovided to the location center 142.

The base stations located at their cell sites may be coupled by varioustransport facilities 176 such as leased lines, frame relay, T-Carrierlinks, optical fiber links or by microwave communication links.

When the mobile station is powered on and in the idle state, itconstantly monitors the pilot signal transmissions from each of the basestations located at nearby cell sites. As illustrated in FIG. 3, basestation/sector coverage areas may often overlap both in the context of asingle CMRS base station network, and also in the context of multipleCMRS base station networks, thus enabling mobile stations to detect,and, in the case of certain technologies, communicate simultaneouslyalong both the forward and reverse paths, with multiple basestations/sectors, either with a single CMRS network or, in the case ofhand-offs and roaming, multiple CMRS network equipment. In FIG. 3 theconstantly radiating pilot signals from base station sectors 122 a, 22 band 122 c are detectable by mobile station 140 at its location. Themobile station 140 scans each pilot channel, which corresponds to agiven base station/sector ID, and determines which cell it is in bycomparing signals strengths of pilot signals transmitted from theseparticular cell-sites.

The mobile station 140 then initiates a registration request with themobile switch center 112 a, via the base station controller (not shown).The mobile switch center 112 a determines whether or not the mobilestation 140 is allowed to proceed with the registration process (exceptin the case of a 911 call, wherein no registration process is required).At this point, calls may be originated from the mobile station 140 orcalls or short message service messages can be received from the mobileswitch center 112 a.

As shown in FIG. 2, the mobile switch center 112 communicates asappropriate, with a class 4/5 wireline telephony circuit switch or othercentral offices, with telephone trunks in communication with the publicswitch telephone network (PSTN) 124. Such central offices connect towireline stations, such as telephones, or any communication devicecompatible with the line, such as a personal or home base station. ThePSTN may also provide connections to long distance networks and othernetworks.

The mobile switch center 112 may also utilize IS/41 data circuits ortrunks 522, which in turn connects to a service control point 104,using, for example, signaling system #7 (SS7) signaling link protocolsfor intelligent call processing, as one skilled in the art willunderstand. In the case of wireless advanced intelligent network (AIN)services such trunks and protocols are used for call routinginstructions of calls interacting with the mobile switch center 112 orany switch capable of providing service switching point functions, andthe public switched telephone network (PSTN) 124, with possibletermination back to the wireless network. In the case of an mobilestation 140 in communication with a corresponding home or office basestation (HBS) 160, the HBS 160 controls, processes and interfaces themobile station 140 to the PSTN 124, in a manner similar to a cordlesstelephone system, except that added AIN logic within, for example, theservice control point (SCP) 104 is used to determine if the mobilestation 140 is being controlled by-the HBS 160 or a wireless basestation 122. Regarding non-HBS calls, the mobile switch center 112 maydirect calls between mobile stations 140 via the appropriate cell sitebase stations 122 a through 122 h since such mobile stations 140 do nottypically communicate directly with one another in such wirelessstandards as CDMA, TDMA NAMPS, AMPS and GSM.

Referring again to FIG. 2, the Location system 142 interfaces with themobile switch center 112 either via dedicated transport facilities 178,using for example, any number of LAN/WAN technologies, such as Ethernet,fast Ethernet, frame relay, virtual private networks, etc., or via thePSTN 124 (not shown). The location system 142 receives autonomous (e.g.,unsolicited) or command/response messages regarding, for example: (a)the wireless network states, including for example, the fact that a basestation has been taken in or out of service, (b) mobile station 140 andBS 122 radio frequency (RF) signal measurements, (c) notifications froma SCP 104 indicating that an HBS 160 has detected and registered withthe SCP 104 the mobile station 140 corresponding to the HBS 160, and (d)any distributed antenna systems 168. Conversely, the location system 142provides data and control information to each of the above components in(a)-(d). Additionally, the Location system 142 may provide locationinformation to a mobile station 140, via a BS 122, using, for examplethe short message service protocol, or any data communication protocolsupported by the air interface between the base station and the mobilestation. Interface 106 connecting the location system 142 with theservice control point 104 may also be required in the event the homelocation register and/or the home base station AIN function is locatedin the SCP 104.

Assuming the wireless technology CDMA is used, each BS 122 a, 122 b, 122c, through 122 g uses a time offset of the pilot PN sequence to identifya forward CDMA pilot channel. Furthermore, time offsets, in CDMA chipsizes, may be re-used within a PCS system, thus providing efficient useof pilot time offset chips, thus achieving spectrum efficiency.

The use of distributed antennas is another technique for improving orextending the RF coverage of a radio coverage area 120 of a wirelesssystem. Such distributed antennas are typically used in buildings orother areas of dense clutter, such as numerous walls, partitions and/orsimilar structures causing substantial signal attenuation. As shown inFIGS. 6, 9, 10, 11, and 13, distributed antennas 168 are typicallyconnected together in a serial fashion for communicating with one ormore infrastructure base stations 122. Distributed antennas may beconnected to the mobile switch center 112 via various air interfaces, asshown in FIGS. 10 and 11, or alternatively distributed antennas may beconnected to the MSC via a directed connection to a base station 122 asshown in FIG. 9, or via a private branch exchange (PBX) as shown in FIG.13.

Referring to FIG. 11, distributed antennas 168 are useful particularlyin wireless system configurations involving microcells, and potentiallyindoor environments, such as wireless systems in communication withprivate branch exchange systems (reference FIG. 13) in business offices,and in wireless local loop applications (not shown) as one skilled inthe art will understand. Additionally, a distributed antenna embodimentcan provide significant improvements in decreasing location error, ascompared with an indoor mobile station 140 (reference FIG. 11) user witha wireless connection to an outdoor, infrastructure base station 122, asillustrated in FIGS. 11, 12, 13 and 14.

Mobile Station Description

As an example of a mobile station 140, such a mobile station will bedescribed using CDMA technology. FIG. 15 illustrates a typical blockdiagram of the functional components of a CDMA mobile station (MS) 140,based on the patent, “Diversity Receiver in a CDMA Cellular TelephoneSystem”, U.S. Pat. No. 5,109,390. The MS 140 contains an antenna 510coupled through diplexer 512 to analog receiver 514 and transmit poweramplifier 516. Antenna 510 and diplexer 512 permit simultaneoustransmission and reception of signals through an antenna 510. Antenna510 collects transmitted signals and provides them through diplexer 512to analog receiver 514. Receiver 514 receives the RF frequency signals,typically either in the 800-900 MHZ or 1.8-1.9 GHz band, from diplexer512, for amplification and frequency down conversion to an intermediatefrequency (IF). Translation is accomplished through the use of afrequency synthesizer of standard design which permits the receiver 514to be tuned to any of the frequencies within the designated receivefrequency band. The IF signal is passed through a surface acoustic wavebandpass filter, typically of 1.25 MHZ bandwidth, to match the waveformof the signal transmitted by a base station 122. Receiver 514 alsoprovides an analog to digital converter (not shown) for converting theIF signal to a digital signal. The digital signal is provided to each offour or more data receivers (520, 522, 524, and 526), one of which is asearcher receiver (526) with the remainder being data receivers, as oneskilled in the art will understand.

Analog receiver 514 also performs a open-loop type of power controlfunction for adjusting the transmit power of the mobile station 140 onthe reverse link channel. Receiver 514 measures the forward link signalstrength of the signals from base stations 122, then generates an analogpower control signal to circuitry in the transmit power amplifier 516,which can effect a range up to about 80 dB. The power control for thetransmit power amplifier 516 is also supplemented by a closed-loop powercontrol or mobile attenuation code (MAC) control parameter sent to themobile station 140 via the air (i.e., wireless) interface from a BS 122,with either the CMAC or VMAC command (as one knowledgeable in CDMAstandards will understand). The MAC can take on one of eight values 0through 7, which effect a closed loop to raise or lower the powercorrection. The transmit amplifier 516 may utilize one of three transmitpower classes when transmitting within a transmitted power control groupin the 800-900 MHZ cellular band: class I (1 to 8 dBW), class II (−3 to4 dBW), or class III (−7 to 0 dBW), for a close “32 dB. In the PCS1.8-1.9 GHz band five classes are defined: class I (−2 to 3 dBW), classII (−7 to 0 dBW), class III (−12 to −3 dBW), class IV (−17 to −6 dBW),class V (−22 to −9 dBW), for a closed-loop range of about” 40 dB. Themobile station 140 power class and transmit power level for acommunicating mobile station 140 is known to the wireless infrastructurenetwork, and may be utilized for location estimation, as is describedhereinbelow.

The digitized IF signal may contain the signals from several telephonecalls together with the pilot channels and multipath delayed signalsfrom each of several pilot channels. Searcher receiver 526, undercontrol of control processor 534, continuously scans the time domainaround the nominal time delay offsets of pilot channels contained withinthe active, candidate, neighboring and remaining sets of pilot channels.The initial sets of pilot channels and a defined search window size foreach set are provided by a control message from a BS 122 via the airinterface to the mobile station 140. The searcher receiver 526 measuresthe strength of any reception of a desired waveform at times other thanthe nominal time and measures each pilot channel's arrival time relativeto each pilot's PN sequence offset value. Receiver 526 also comparessignal strength in the received signals. Receiver 526 provides a signalstrength signal to control processor 534 indicative of the strongestsignals and relative time relationships.

Control processor 534 provides signals to control digital data receivers520, 522 and 524 such that each of these receivers processes a differentone of the strongest signals. Note, as one skilled in the art willunderstand, the strongest signal, or finger, may not be the signal ofshortest arrival time, but rather may be a reflected, and thereforedelayed, signal (such reflected denoted collectively as “multipath”).Data receivers 520, 522 and 524 may track and process multipath signalsfrom the same forward channel pilot channel offset or from a differentforward channel pilot offset. In the case where a different pilotchannel offset signal is of greater strength than the current cell site(or more specifically the current base station 122) pilot channeloffset, then control processor 534 generates a control message fortransmission on a reverse channel from the mobile station 140 to thecurrent BS 122, requesting a transfer of the call, or a soft hand-off,to the now strongest cell site Base station 122. Note that each of thefour receivers 520, 522, 524 and 526 can be directed independently fromeach other. The three data receivers 520, 522, and 524 are capable oftracking and demodulating multipath signals from of the forward CDMApilot channel. Thus data receivers 520, 522 and 524 may providereception of information via separate multipath signals from one BS 122(e.g., in particular, an antenna face of a sectored antenna at the BS122, or reception of signals from a number of sectors at the same BS122, or reception of signals from multiple BSs 122 or their antennafaces of sectored antennas. Upon receiving a CDMA pilot measurementrequest order command, or whenever (a) the mobile station 140 detects apilot signal of sufficient strength, not associated with any of theassigned forward traffic channels currently assigned, or (b) the mobilestation 140 is in preparation for a soft or hard hand-off, then thesearcher receiver 526 responds by measuring and reporting the strengthsof received pilots and the receiver's definition of the pilot arrivaltime of the earliest useable multipath component of the pilot, in unitsof PN chips (one chip=0.813802 microseconds). The receiver 526 computesthe strength of a pilot by adding the ratios of received pilot energyper chip E_(c), to total received spectral density, I_(o), of at most kuseable multipath components, where k is the number of data receiverssupported in the mobile station 140.

The outputs of data receivers 520, 522, and 526 are provided todiversity combiner and decoder circuitry 538 (i.e., simply diversitycombiner). The diversity combiner 538 performs the function of adjustingthe timing of a plurality of streams of received signals into alignmentand adds them together. In performing this function, the diversitycombiner 538 may utilize a maximal ratio diversity combiner technique.The resulting combined signal stream is then decoded using a forwardstream error detection contained within the diversity combiner. Thedecoded result is then passed on to the user digital baseband circuitry542.

The user digital baseband circuitry 542 typically includes a digitalvocoder which decodes the signals from diversity combiner 538, and thenoutputs the results to a digital to analog (D/A) converter (not shown).The output of the D/A serves as an interface with telephony circuitryfor providing mobile station 140 user analog output information signalsto the user corresponding to the information provided from diversitycombiner 538.

User analog voice signals typically provided through an mobile station140 are provided as an input to baseband circuitry 542. Baseband 542serves as an interface with a handset or any other type of peripheraldevice, to the user for audio communication. Baseband circuitry 542includes an analog to digital (A/D) converter which converts userinformation signals from analog form into a digital form. This digitalform is then input to a vocoder (not shown) for encoding, which includesa forward error correction function. The resulting encoded signals arethen output to transmit modulator 546.

Transmit modulator 546 modulates the encoded signal on a PN carriersignal whose PN sequence is based on the assigned address function for awireless call. The PN sequence is determined by the control processor534 from call setup information that was previously transmitted by acell site BS 122 and decoded by the receivers 520, 522, 524 as oneskilled in the art will understand. The output of transmit modulator 546is provided to transmit power control circuitry 550. Note that signaltransmission power is controlled partially by an open-loop analog powercontrol signal provided from receiver 514. In addition, control bits arealso transmitted by the controlling BS 122 in the form of a supplementalclosed-loop power adjustment command and are processed by data receivers520, 522. In response to this command, control processor 534 generates adigital power control signal that is provided to the transmit poweramplifier 516. Transmit power control 550 also provides the digitizedand encoded user information signals in an IF format to output to thetransmit power amplifier 516. The transmit power amplifier 516 convertsthe IF format signals into an RF frequency by mixing this signal with afrequency synthesizer (not shown) output signal for providing acorresponding signal at the proper output transmission frequency signal.Subsequently, transmit power amplifier 516 amplifies the signal to thefinal power output level. The transmission signal is then output fromthe transmit power amplifier 516 to the diplexer 512. The diplexer 512then couples the transmission signal to antenna 510 for air interfacetransmission to the infrastructure base stations 122.

Additionally, note that control processor 534 is also responsive tovarious control and information request messages from the controlling BS122, including for example, sync channel messages, the system parametersmessages, in-traffic system parameters messages, paging/alert messages,registration messages, status requests, power control parametersmessages and hand-off direction messages, as one skilled in the art willunderstand.

Referring still to a CDMA mobile station 140, in one embodiment of thepresent invention, the above-described standard CDMA mobile stationarchitecture in an mobile station 140 is sufficient. However, in asecond embodiment, this architecture may be modified in minor, costeffective ways so that additional information may be transmitted from anmobile station 140 to the BS 122. The modifications for this secondembodiment will now be described. The following modifications, eithertogether or in any combination, provide improvements in locationaccuracy from the perspective of capturing RF measurement data: (1)increasing measurement quantity, (2) improving measurement transmission,(3) extending the pilot set and search, (4) extending the pilot signalreporting capabilities, (5) decreasing the Quantization size of theunits used to report the pilot PN phase arrival time, (6) improving theaccuracy of the mobile and base station time reference, and (7)increasing the number of data receivers and related circuitry, forcorrelation tracking of a larger plurality of pilot channels and each oftheir multipath signals.

Using the standard system parameters overhead message in the pagingchannel as one method of reporting to the base station the signalstrengths and delays of detectable pilot channels, a mobile station hasvarious timers indicating the upper bounds of time needed to respond toa request, and to bid for access to the forward channel (if not alreadyusing it's assigned traffic channel). These timers restrict thefrequency of measurement reporting and thus limit the aggregate amountof measurement data which can be sent in a given time period.

For example, CDMA standard timer T_(33m) establishes the maximum time ofa mobile station to enter the update overhead information substate ofthe system access state to respond to messages received while in themobile station idle state, typically 0.3 seconds. Timer T_(58m), themaximum time for the mobile station to respond to one service optionrequest, is typically 0.2 seconds. Thus during a period of about fiveseconds, this measurement reporting method would provide for a maximumof about fifteen measurements.

However the same CDMA receiver design infrastructure, with slightcircuitry modification can be used to support improved measurementtransmission.

In order to collect a data ensemble of RF measurements that represents astatistically significant representation of data values in ageographical area of interest, it is the intention that the second(CDMA) mobile station 140 embodiment be capable of sending to thenetwork base station infrastructure approximately 128 samples of eachmultipath peak signal strength and its relative delay, for eachdetectable pilot channel, in less than a preferred period of about fiveseconds. In order to transmit this amount of data, other means areneeded to efficiently send the needed data to the network (i.e., fromthe mobile station to the base station, and then to forward data to thewireless switch, and then to forward data to the Location Center).

The CDMA air interface standard provides several means for transmittingdata at higher rates. The Data Burst message can be used, or variousblank-and-burst, dim-and-burst multiplex options can be used, and wellas selecting various service options 2 through 9, through the setup of anormal voice or data telephone call. In one embodiment,, the user dialsa speed number representing a data-type call to the Location Center 142,which initiates a command to the mobile station 140, responsive by themobile station 140, which then provides the location center 142, via thebase station 122, mobile switch center 112 with the needed measurementdata.

Referring to FIG. 16, in one embodiment a software controllable dataconnection or path 49 is established between the control processor 46,and the user digital baseband 30 functional components in the mobilestation, a much larger quantity of RF measurements, on the order of 128data samples, can be transmitted as a data burst, multiplexed, or sentby other means such as a data circuit call, back to the network, and tothe Location Center. Note that the existing connection between thecontrol processor 534 and the transmit modulator 546 may also be used,as well via any other virtual path, such as softwareregister-to-register move instructions, as long as sufficient signalmeasurement content and data samples can be sent to the wireless networkand the location center 142 via the associated interfaces. Those skilledin the art will understand the wireless network consists of the basestation, mobile switch center, and related infrastructure equipment,interfaces and facilities circuits to telemeter the measurement contentand data samples to the location center 142. Additional design issuesinclude, for example, the fact that existing memory in the mobilestation must be allocated to the temporary storage of RF samplemeasurements, and new control means, such as selecting a future usecontrol bit pattern in the CDMA air standard, are required to telemeter,preferably upon command, RF measurement sample data to the LocationCenter 142 in FIG. 1. In the case where a location request is receivedby the location engine 139 in the location center 142, the locationengine 139 initiates a message to the mobile station 140 via a signalprocessing subsystem and the location center mobile switch centerphysical interface, the location applications programming interface 136(e.g., FIG. 36, L-API-MSC) for the mobile switch center 112 and thewireless network infrastructure.

The addition of a controllable data connection or path 49 can be easilyperformed by CDMA application-specific integrated circuit (ASIC)manufacturers. In the case of one ASIC manufacturer known to theauthors, the Qualcomm ASIC chip mobile station modem, model number MSM2300, provides both the control processor function 534 and the userdigital baseband 542 functions or the same chip, thus the externalpinout physical configuration would not have to change to accommodatethe wireless location software controllable data connection or path 49modification.

If the mobile station 140 searcher receiver detects 4 pilots with 4multipaths each, with each measurement consisting of a pilot index,finger identification, multipath signal strength, and multipath arrivaltime, then about 480 bytes are needed per measurement. Assuming thesearcher receiver performs one measurement every 10 microseconds, about1 second is needed to compile and buffer each sample of 128 measurementsper sample, or about 48 kilobytes. Using a typical 9600 kbps CDMA datachannel between the mobile station 140 and a BS 122, and assuming a 50percent overhead, the mobile station can complete the collection andtransmission of a location measurement sample in less than ten seconds,which is within a reasonable period for satisfying a location request.

Network Data Services

The implementation of the data services required to telemeter thenecessary signal measurements may be performed in any of severalembodiments. In one embodiment the location signal measurementsrequest-response application message set utilizes the air interfaceservices provided by the spare bits and digital control words notcurrently in the air interface standards IS-95 and ANSI-J-STD-008. Suchbits and control words can be reserved for the purpose of requesting andproviding the required location signal measurements discussed herein.Using this embodiment the base station and mobile switch center must bemodified to support the interworking function required between thelocation center and the mobile station. In a second embodiment thelocation signal measurements request-response application message set isimplemented using service options 4 and 12, which provides asynchronousdata transmission capability, as defined in TR45 Data Standard, Asyncand Fax Section, document number TIA/EIA/IS-DATA. 4. Using this secondembodiment, the mobile station control processor provides, or wouldinterface with a function emulating mobile termination 0 or 2 servicesat the R_(m) network reference point. The L-API 14 then provides, orwould interface with a function emulating the physical interfaceconnecting a data circuit-terminating equipment (DCE) to the PSTN at theW network reference point, in communication with the PSTN, which is alsoin communication with reference point Ai, which is in communication withreference point U_(m), which is in turn in communication with referencepoint R_(m,). An advantage of this embodiment is that no ASIC or circuitboard modifications are needed in the mobile station.

The ANSI standards J-008 and IS-95 provide several means for the basestation 122 to establish and to extend the search window size that themobile station 140 should use in its scanning process, and to identifyfurther pilots. For location purposes, either existing standardparameters can be extended, or a location message request from the Basestation can inform the searcher receiver of the mobile station to extendits search range, as necessary, to capture all relevant base stationpilots and their multipath fingers, in order to complete the locationmeasurement sample.

The search performance criteria defined in ANSI IS-98, RecommendedMinimum Performance Standards for Dual Mode, can be increased asappropriate to accommodate a larger set of potentially detectable basestations, including Location Base stations and Mobile Base stations.Additionally the search window table size for various search windowvalues must be increased to accommodate new pilot channel pn-offsetsassociated with Location Base Stations and Mobile Base stations.

Existing standard parameters include, for example using the In-trafficSystem Parameters Message, the values SRCH_WIN_A (for active andcandidate set), SRCH_WIN_N (for neighboring set), and SRCH_SIN_R (forremaining set) can be used to cause the searcher receiver to increaseits search area to detect and thus measure as many pilots as can bedetected in the area. Extending the range of T_ADD and T_DROP parameterscan also be used to facilitate the mobile to retain data on additionalpilots in the area. The extended neighbor list message is used to informthe mobile station of the necessary characteristics of neighboring pilotsignals. For example if location base stations are used on a differentfrequency assignment, and/or utilize unique, non-public pilot PNsequence offset indices, for example, in using increments other than 64PN chips, then the extended neighbor list message can be used toinstruct the mobile station to scan for those types of base stations,accordingly.

There can be several combinations of delay spread signal strengthmeasurements made available to the location center, from the mobilestation 140. In some cases the mobile station 140 may detect up to threeto four pilot channels (representing 3-4 base stations), or as few asone signal from one pilot channel.

For each pilot channel detection case, multiple, up to three to fourfingers, or multipath signals may be detected per pilot channel.

Note that multiple multipath signals, or multiple “fingers” could existfrom a less-strong BS pilot signal, or in any of several combinations,which can depend widely upon the mobile station's location within thebase station environment.

By modifying the CDMA Base station, mobile station and controllercapabilities to provide the location center 142 with data that exceedsthe 1:1 fingers to data receiver correspondence, additional informationcan be collected and processed in order to further improve the accuracyof the location estimate. A control message from the location center 142and carried through the network, is sent to the control processor in themobile station, requiring the searcher receiver in the mobile station totransmit to the location center 142 via the network, all detectabledelay spread fingers related to each detectable pilot channel.

In one embodiment the control message is implemented in the CDMAreceiver via a multiplexing technique, including appropriatemanipulation of the hand-off parameters T_ADDs, T_DROPs, search windowand the active, neighbor and remaining pilot sets held within the mobilestation' memory.

Although the CDMA ANSI J-STD 008 requires reporting of the pilot channelarrival time in a time period of units of one chip size, or 813.802nanoseconds, typical CDMA receivers contain an internal Quantizationinterval of one eighth chip size.

Within the mobile station, by modifying the time of arrival messageresponse message to output the delay value in unit increments ofone-eighth chip size, the precision of location accuracy can beincreased from about 800 feet in radius to about 110 feet. At the basestation the arrival time measurement is forwarded in one-eighth units tothe Location Center. A multiplier function applied to the receivedmeasurement at the base station rescales the measurement for routineCDMA control and monitoring purposes, in order to be consistent with theCDMA standard. In order to distinguish among several mobile stationmodels which report arrival time in either one-eighth chip units or onechip unit sizes, an encoding can be used in the mobile station'shardware or software identifications, telemetered to the base stationand Location Center, in order to determine the arrival time measurementunits. In one embodiment the analog receiver in the mobile stationutilizes a clock signal which runs eight times faster than the clockoriginally disclosed in the Gilhousen patent, U.S. Pat. No. 5,109,390.In this manner the digital signal provided to the data receivers and thesearcher receiver will include an improved resolution in ability todetect delay spread signals, which are directly used to improve wirelesslocation.

Although the CDMA air interface standard only requires a 1,000nanosecond tolerance accuracy within respect to the base station,location accuracy can be improved if manufacturing calibrationprecision's are held to within tighter tolerances, such as less than 250nanoseconds. However in any given location request, as long as the basestation to base station tolerances are tuned properly to an amount lessthan 500 nanoseconds, then very good location estimates can be performeddue to the self canceling time effect geometries typically present inmulti pilot channel detection found in urban and suburban areas.

Increasing the typical number of data receivers in either the mobilestation or base station provide added capabilities to lock and trackmore delay spread fingers and respective base station pilot channels.The resulting additional information, if available in a given radiocoverage area 120 in FIG. 1, can be used for enhanced location estimateaccuracy due to confluence or voting methods which can be deployed atthe Location system 142.

Fuzzy Logic for Vertical Location

In certain cases wireless location signals are received representingdistributed antennas (or other base stations) across building floorboundaries being received from a specific floor on a multi-storiedbuilding. As a specific example, consider signals are being receivedfrom both the 40th and the 41^(st) floor; the objective is to resolvethe ambiguity of the situation. Fuzzy logic is used to resolve thisambiguity. The determination as to which floor the user of the mobilestation is on is based on the strength of the signal, S, and the pastreliability of the information associated with the two antennae, R. Thespaces of S and R are discretized using fuzzy sets. The strength isdefined as being: (1) VERY STRONG (VS), (2) STRONG (S), (3) WEAK (W),and (4) VERY WEAK (VW) as defined by membership functions. Thereliability of information is defined as being: (1) VERY RELIABLE (VR),(2) RELIABLE (R), and (3) NOT RELIABLE (NR), again as defined bymembership functions. A fuzzy relation or mapping is described whichdescretizes how confident it is that the signal is coming for a givenfloor, e.g., the 40th floor, using the following notation: VS S W VW VR1.0 0.85 0.45 0.2 R 0.85 0.6 0.4 0.1 NR 0.6 0.4 0.3 0.0

The above relation matrix is read, for example, that when the signalinformation is RELIABLE and the strength is WEAK, then the confidencethat the signal is coming from the 40th floor is 0.4. A similar fuzzyrelation matrix is established for the distributed antenna on the 41stfloor, and thus the result would be a confidence factor associated withthe mobile station being located on either floor. A single solution,that is, whether the mobile station is on the 40th or 41st floor isdetermined using a compositional rule of inference. The compositionalrule of inference is a function that prescribes a mechanism forconsolidating membership function values into a single crisp function.This function can take a variety of forms including max-min composition,max-product composition. etc. The compositional rule of inference can beimplemented, for example, by a summing junction which collects theresults of each firing rule. The summing junction's output is thenprovided to a centroidal defuzzier which provides the discretizedoutput.

FIG. 43 indicates the addition of a fuzzy logic module 41 whichoptionally discretizes the wireless location estimate output from theTOA/TDOA location estimator module 8. In the above case fuzzy logicrules related to the distributed antenna relation matrix would be firedor activated as a result of examining the message header data structurethat indicates that the location estimate was the result of adistributed antenna case around the 40th and 41st floor of a particularbuilding within which such fuzzy relations exist or in any otherlocalized case wherein such fuzzy relations have been predetermined.Otherwise, in cases where no such fuzzy rules apply, the locationestimate is passed to the recipient without further discretization.

Note that the confidence associated with the location of the mobilestation can be considered a function of several variables, not just thetwo (S and R) described above. For instance, it would not beunreasonable to segregate the reliability information by time signaldelay as determined within this invention. The fuzzy relation is capableof handling a variety of such situations. Thus which floor the mobilestation is on can be considered to be a function of numerous variables;the ultimate decision can be made based on a great deal of information.

Location Center—Network Elements API Description

A location application programming interface 14 (FIG. 1), or L-API, isrequired between the location system's 142 signal processor 20 and themobile switch center 12 network element type, in order to send andreceive various control, signals and data messages for wireless locationpurposes. The L-API 14 is implemented using a preferably high-capacityphysical layer communications interface, such as IEEE standard 802.3 (10baseT Ethernet), although other physical layer interfaces could be used,such as fiber optic ATM, frame relay, etc. Two forms of APIimplementation are possible. In the first case the control signals anddata messages are realized using the mobile switch center 112 vendor'snative operations messages inherent in the product offering, without anyspecial modifications. In the second case the L-API 14 includes a fullsuite of commands and messaging content specifically optimized forwireless location purposes, which may require some, although minordevelopment on the part of the mobile switch center vendor. A minimumset of L-API message types includes:

A first message type, an autonomous notification message from the mobileswitch center 112 to the location system 142, is required in the event awireless enhanced 9-1-1 call has been sent to the mobile switch centerfrom a mobile station 140, including the mobile identification number(MIN), along with various CMRS identification and mobile stationdetected active, candidate, neighbor and remaining pilot setinformation, pilot strength measurements message.

A second message type, forward path request-response message, fromlocation system 142 to mobile switch center 112, is required to requesta mobile station (MS) for signal measurements and hand-off information,with a response message back from the mobile switch center 112 to thelocation system 142, along with various CMRS identification.

A third message type, Reverse path request-response message, fromlocation system 142 to mobile switch center 112, to a BS for signalmeasurements received at the BS and hand-off information, for a givenmobile station MIN, along with various CMRS identification. It ispreferable for the received signal strength measurements performed atthe mobile station along the forward path, and at the base station alongthe reverse path, to be reported in a variable-length data structure asfollows: for each pilot channel offset, include the phase of theearliest arriving usable multipath component pilot PN sequence relativeto the zero offset pilot PN sequence of this pilot, termed pilot PNphase or pilot arrival, in units of one-eighth PN chip, instead of unitsof one PN chip as stated in the standards. Furthermore, in accordancewith the standards, the pilot strength shall be included, measured basedon at most k usable components, where k is the number of demodulatingelements supported by the receiver system. In addition the total numberof each detectable multipath components shall be reported. In additioneach multipath component, for a given pilot, shall be identified by bothits delay component and signal strength, for inclusion in the signalmeasurements to the location system 142. Regarding each individualmultipath component, signal strength is expressed as is commonly known,by adding the ratios of received pilot-multipath component energy perchip, E_(c), to total received spectral density (noise and signals),i_(o) of at most that one multipath component (i.e., k is equal to one).

A fourth message type, an autonomous notification message from themobile switch center 112 to the location system 142 is required, in theevent of a mobile station hand-off state change, along with various CMRSidentification.

In order to implement additional location functions such as wide arealocation, wherein location is determined across roaming boundaries,out-of-coverage area conditions or mobile station 140 turned off, andhome base station applications, the L-API 14 must include access to andreceive data from a data store contained in the home location register(HLR) network element type associated with the mobile switch center 112.

A fifth message type is required which provides the location system 142with the mobile station MIN, hand-off, along with various CMRSidentification information (e.g., old and new state changes, old and newBS identifications, and hand-offs to another CMRS), roaming location andstatus changes. A typical communications protocol such as SignalingSystem number 7, running on a V.35 communications channel could be usedfor implementation, but numerous other protocols (e.g., TCIP/IP, ROSE,CMISE, etc.) could be used to implement this capability. If the homelocation register is local to the mobile switch center 112 then theLC—mobile switch center communications link could be used, otherwise aseparate communications link is used between the location system 142 andthe home location register.

A sixth message type, an autonomous notification message type issuedfrom the location system 142 to the home location register, is requiredfor those location applications that rely on an alert from the homelocation register when ever a particular mobile station state changeoccurs, along with various CMRS identification. Consider the casewherein an mobile station 140 whose location is to be trackedconstantly. In such cases a history of locations is maintained in thelocation system 142. Should the mobile station 140 user turn off thepower, or exit from the coverage area, then by using previous locationvalues a vector and approximate velocity can be determined. This sixthmessage type provides a notification message from the home locationregister to the location system 142 whenever a previously identifiedmobile station MIN has a state change. Examples of state changes includecases where the base station 122 discovers the mobile station 140 hastraveled to another base station, or that the current primary basestation 122 can no longer communicate with the mobile station 140 (i.e.,no power), or that a new registration has occurred. In general thismessage type should support the notification from the home locationregister to the location system 142 of all messaging and data associatedwith the nine types of registration, in the case of CDMA. Specificallythese include power-up, power-down, timer-based, distance-based,zone-based, parameter-change, ordered, implicit and traffic channelregistration. The location system 142 should also be informed of theregistration enablement status of each type of registration, which canbe provided to the location system 142 via a redirection of the systemsparameters message. It should also be possible (in a seventh messagetype) for the location system 142 to initiate an ordered registrationthrough an order message, from the location system 142 to the mobileswitch center 112. The mobile switch center 112 then shall route themessage to the appropriate base station, and then to the mobile station.The location system 142 should also be able to receive the results ofthe message.

In order to implement additional location functions such as providingusers with location information and routing instructions to certainlocations via the wireless short message text paging service, an L-API14 is required between the location system 142 and the network elementtype used to implement the short message service. Such network elementsmay be termed an intelligent peripheral or a service node. A number ofexisting paging interfaces have been proposed in standards bodies, andone or more modifications can be made to accommodate L-API 14 content.In any case, the following L-API addition is required: an eighth messagetype which allows the location system 142 to send a text messagecontaining location information or instructions to a particular mobilestation MIN, and a related message to verify response. Optionally inanother, ninth message type, an autonomous message may be provided toalert the location system 142 under conditions wherein a state changeoccurs on a previously pending text message. This last message typeprovides improved quality feedback to the initiating party regarding theacceptance situation of the attempted-to-send page.

Utilizing Multiple CMRS Infrastructure in a Shared Coverage Area

As a consequence in practical deployment situations that base stationsare not placed in a uniform manner in a geographical area, and the factthat variable and fixed clutter introduce a variety of signalmeasurements which can result in the provision of an ambiguous locationestimation, a novel aspect of this patent includes the utilization ofthe inherent ability of the wireless protocol and receiver design torequest and receive signal measurements along the forward and reverseair interface communications path with a given mobile station and othercommercial mobile radio service providers, in cases where multipleservice providers share a common coverage area. Thus in a coverage areashared by two service providers A and B, utilization of received signalmeasurements from both service provider A and service provider B can beused by the location center as unique, orthogonal information to bothresolve ambiguous location estimates and to further improve the locationestimate accuracy.

The CDMA air interface, for example, provides a soft hand-off capabilityfor the mobile station to hand-off a voice communication channel toanother base station, and even to another CMRS provider, termed a hardhand-off.

Referring to FIG. 3, assume three sectored base stations 122 a, 122 b,and 122 c, in communication with mobile switch center-A 112 a, are ownedand operated by CMRS provider A. Further, assume three sectored basestations 122 d and 122 e, in communication with mobile switch center-B112 b, are owned and operated by CMRS provider B, and that the coveragearea with CMRS-A and CMRS-B substantially overlap. In order to locate amobile station 140 whose subscriber normally does business with CMRSprovider A, assume that the receiver of mobile station 140 can detectsignals from base stations 122 a, 122 b, and 122 c, as well as from basestations 122 d and 122 e, although normal mode use would preclude suchmeasurements from being initiated. Assume further that the resultinglocation estimate 131 (FIG. 5), generated from the location center 142contains either an ambiguous location estimate value pair, or otherwisecannot render a location estimate with the desired range of accuracy.

From an inspection of the overall base station geometry of base stationsowned by CMRS A and CMRS B it is evident that a strong possibilityexists that either 1.) the receivers in mobile station 140 have thepossibility to detect the pilot channels associated with base stations122 d and 122 e; 2.) the receivers in base stations 122 d and 122 e havethe possibility to detect the transmitter signal from mobile station140. The location system 142 contains a data store of both CMRSprovider's base station geometries and is in communication with eachmobile switch center-A 112 a and mobile switch center-B 112 b. Anapplication in the location system 142 sends a control message to themobile station 140, instructing the mobile station to tune its searcherreceiver to listen for and report back signal measurement data regardingthe pilot channel information associated with base stations 122 d and122 e, in addition to a request to report of pilot signals relative tobase stations 122 a, 122 b, and 122 c. Similarly the application in thelocation system 142 sends messages to each of base stations 122 d and122 e, with instructions to take signal measurements and report back theresulting information regarding the mobile stations transmitter 140.Since the signaling information from base stations 122 d and 122 e arebased on a substantially different location geometry, the resultantinformation is orthogonal and thus can be used by the location center toprovide enhanced location estimates.

If appropriate, a variation of the above process includes a locationcenter initiated forced hard hand-off of the mobile station from aprimary base station, e.g., 122 b associated with CMRS-A, to a newprimary base station associated with CMRS-B, e.g., 122 d. A forcedhand-off will further provide improvements in reducing systemic timingerrors which may be inherent among base stations owned by differentCMRS. After the appropriate signal measurements have been reported thelocation system 142 can revert the hand-off back to the original CMRS.Other location system components shown in FIG. 3 include the L-API 14which includes the location applications programming interface 136(L-API-MSC) as a communications interface with multiple CMRS mobileswitching centers, via physical interfaces 176 a and 176 b.

In order to provide the most economically efficient and accuratewireless location service capabilities among multiple CMRS providers ina shared coverage area, a common location applications programminginterface (L-API 14) is highly desirable. A common interface alsosupports the natural competitive behaviors among wireless consumers andCMRS by providing flexible relationships among consumers who may want toswitch service providers, yet retain consistent wireless locationservices for public safety. This approach minimizes the L-API design anddeployment costs among infrastructure vendors and location serviceproviders in a shared coverage area. Based on a L-API between a wirelesslocation center and the mobile switch centers of multiple CMRS, a novelaspect of this invention further includes a method and process thatprovides account management clearing house and revenue settlementcapability with appropriate security management controls. Thiscapability is implemented as wireless location control, accounting andsecurity mediation agent functions to compensate CMRS providers forproviding various location-specific network services as describedherein.

As wireless location requests are sent to the location center for agiven CMRS, operated by a wireless location service provider (WLSP), thelocation center: 1.) assesses the appropriateness of solicitingadditional signal and control measurements from another CMRS' basestation in the same coverage area, in order to improve the quality ofthe location estimate, 2.) accesses, requests and receives signal andcontrol information with another CMRS base station infrastructure, 3.)provides as appropriate a record of compensation entitlement between oramong multiple CRMS and WLSPs, and 4.) provides security managementcontrols that protect the privacy needs of wireless customers and theunauthorized sharing of information between or among CMRS. Securitycontrols also include audit trails and controls regarding customeraccess of their location subscriber profile and the administration ofnetwork security processes and related base station parameters andinventory.

Referring to FIG. 5, Location Center-base station access, multiple CMRS,an alternative embodiment is provided to extract the wireless locationsignal measurement data from each base station associated with each ofmultiple CMRS. Given base station 122 i and 122 j are operated by CMRS-Aand base station 122 k and 122 m are operated by CMRS-B, a communicationcircuit provides connectivity with the location application programminginterface—base station (L-API-BS) (not shown). The L-API-BS is incommunication with the L-API 14 in the location center 142. Thecommunications circuit can be any of several conventional transportfacilities, such as a private line circuit, a DS-1 or T-1 carriercircuit, frame relay circuit, microwave circuit, or other datacommunications circuit.

The advantage of this embodiment is that no modifications are requiredby the infrastructure vendor in terms of the embedded operationscircuit, and related functions and systems which otherwise would beneeded to telemeter wireless location signal measurement data from thebase station to the location center 142. The termination equipment (notshown) in communication with the transport facilities, within each basestation typically includes a small computer with an in-circuitconnection, such as an ASIC clip-on device, with connections to thecontrol processor circuitry with the base station in the receiversection. The small computer provides a conversion of the signalsprovided on the in-circuit connection to the ASIC chip, forserialization and transmission to the location center via the transportfacilities.

Home Base Station Description

The Home Base station (HBS) concept in the PCS wireless networkenvironment allows a user's mobile station to be also used as a low costcordless phone, whenever the mobile station is physically near(generally within 700-1,000 feet) of a Home Base station Device (HBSD).This enables the user to avoid the typically higher cost air timecharges associated with traditional wireless service.

The HBSD is similar to ordinary cordless phone transceiver devices incurrent use today, but is modified to function with a PCS wirelessmobile station. Although the HBSD has been typically used at aresidential consumer's home, the HBSD could also be used in businesssettings and other environments.

When a mobile station (MS) is near the HBSD as shown in FIG. 17, and theHBSD detects the presence of a mobile station over the cordless phoneair interface, the HBSD signals the Home Location Register (HLR)software in the Service Control Point in the AIN network associated withthe mobile station and mobile station's home mobile switch center. Thehome location register redirects mobile station terminating calls fromthe network away form the mobile station's mobile identification numberin the mobile switch center, and to the AIN/SSP wireline class V switchwhich connects the wireline number associated with the HBSD. Similarly,the HBSD, upon detecting a mobile station call origination attempt,redirects the mobile station signal from a PCS network fixed basestation, to the control of the HBSD. The HBSD redirects the mobilestation originating call through the wireline network, similar to anyother wireline network call.

A reverse scenario occurs whenever the mobile station and HBSD losecommunication: the mobile station registers in a wireless PCS networkfixed base station, causing redirection of calls to the wirelessnetwork. The cordless phone air interface may be of a vendor proprietarydesign, or it may be a similar design as the CDMA air interface.

In order to perform a location estimate in the HBS concept, a connectionis used between the Location Center (LC) and the home locationregister/HBS application in the SCP. In addition, a new process, termeda Location Notification Process (LNP) within the home locationregister/SCP is used to send a message to the LC, autonomously whenevera state change occurs in the mobile station' (either via a specific listof mobile identification numbers or all mobile identification numbers)registration: registering either to a fixed Base station in the WirelessPCS network or to a HBSD.

Alternatively the process may respond to an on-demand message from theLC to the LNP within the home location register/HBS application. Ineither case a response message from the LNP to the LC provides theinformation regarding whether or not a mobile station is within range ofits, or a designated HBSD. In either case the response message containsa message header information which provides the signal processingsubsystem 20 (equivalently this may be known by signal filteringsubsystem) with the ability to determine and distribute the informationto the HBS First Order Location Estimate Model.

Location using Distributed Antennas Description

CDMA distributed antennas are useful particularly in systemconfigurations involving microcells, and potentially indoorenvironments, such as CDMA PBX (private branch exchange) systems inbusiness offices, and in wireless local loop applications. From a mobilestation location perspective, the distributed antenna configuration canprovide significant improvements in location error, as compared with anindoor mobile station user with a wireless connection to an outdoor,macrocell Base station. Wireless location can be achieved providedcertain methods and procedures (M&Ps) are followed during theinstallation process. Data related to these M&Ps is then used by variouslocation processes discussed elsewhere in this invention.

First, a general description of CDMA distributed antennas is presented,followed by the M&Ps necessary to support wireless location.

In the CDMA distributed antenna concept, a set of simple antennas,placed apart in a given area, similarly to any other cell placementarrangement for coverage objectives, are fed by a common radio signal.Antennas are usually placed such that their coverage patterns aresubstantially or completely overlapped in area of coverage. From awireless location perspective, completely overlapping coverage ispreferred (this approach also improves perceived signal quality by theend users).

The importance of understanding and characterizing the aggregate systemdelay elements is shown in FIG. 6: Distributed Antenna DelayCharacterization. For any given Pilot Channel offset “l”, additionaldelay is introduced by the microwave propagation channel (Point A) andany internal repeater/amplifier equipment (Point B). Each of four delayelements t₁ through t₄ introduce further delay. A mobile stationdetecting all four DA antennas' delayed signals would determine varioussets of cumulative system propagation delays. Since each delay isessentially fixed in a location, such information can be used todetermine the mobile station location within the building. FIG. 7illustrates the effective system timing among the delay elements 324,relative to the GPA system time 336, along each point in the diagramshown in FIG. 6.

FIG. 9: One Exemplary DA Configuration, illustrates a typicalconfiguration where the CDMA base station antenna is also directedconnected to three delay elements and antenna radiators.

The CDMA Base station transmitter common output signal is fed through adistribution coaxial cable system, optical fibers or other means, to astring of two or more antennas. Each antenna is connected to thedistribution cable via a transmission line tap or delay element, whichmay or may not provide further broadband gain. The transmission systemnormally consists of two media channels, one for transmit and one forreceive signals. FIG. 10 illustrates an Alternative DA Configuration,using multi-point microwave antennas connected to individual delayelements and their respective radiating antennas.

FIG. 11: Serving Dense Multi-level buildings via Virtual Pilots,illustrates a typical application where a multi-level building is servedby two base stations with pilot offsets “l” and “j”. Pilot offset “l”serves floor X and pilot offset “j” serves floor Y. As shown, amicrowave link, either active or passive, relays the base stationsignals between the distributed antennas within the building to the basestations.

The main concept is to introduce purposeful delay and multipath signalswith sufficient delay spread for signal discrimination. Each antennaradiates a signal which is substantially delayed with respect to anyother antenna in the area. If two or more paths are available for themobile station receivers with greater than one eighth microseconddifferential path delay (or whatever resolution is available in the CDMAmobile station receivers), then two or more PN receivers in the samemobile station can be employed to separately receive and combine thesesignals and thus achieve processing gains through path diversity.Antennas may be omni-directional or directional.

Delay elements may be simple delay lines such as lengths of coaxialcabling, or other active or passive delay elements, such that thecombination of components provides the needed delay. The transmissionline between the CDMA Base station/PBX and the distributed antennas maybe via a pair of dedicated, beam-focused high gain antennas, and/or arepeater system. Provided sufficient delay exists between the multipathsignals from separate distributed antennas exists, each Data Receiverwithin the mobile station tracks the timing of the received signal it isreceiving. This is accomplished by the technique of correlating thereceived signal by a slightly earlier reference PN and correlating thereceived signal with a slightly late local reference PN. Furtherdistributed antenna details can be seen from Gilhousen, et al, U.S. Pat.No. 5,280,472, assigned to Qualcomm, Inc.

The total measured delay of both forward and reverse link signalsbetween the BS and the mobile station are thus determined naturally bythe CDMA radio receiver designs as a part of the multipath trackingprocess, and can be made available to a location entity for performinglocation estimates of the mobile station.

However, the measurements of delay between a particular distributedantenna and the mobile station will include the aggregate delaycomponents of several mechanisms, beyond the BS pilot PN offset delay.In the case of distributed antenna configurations, the simple TOA orTDOA model which is based solely of the speed of light, must now beadjusted to account for the purposefully introduced delay.

The mobile station measures the arrival time T_(i), for each pilot lreported to the BS. The pilot arrival time is the time of occurrence, asmeasured at the mobile station antenna connection, of the earliestarriving usable multipath of the pilot. The arrival time is measuredrelative to the mobile station' time reference in units of PN chips. Themobile station computes the reported pilot PN phase f_(i) as:f _(i)=(T _(i)+64×PILOT_PN) mod 2¹⁵,

where PILOT_PN is the PN sequence offset of the pilot.

Reference FIG. 6, which illustrates a typical distributed antennaconfiguration consisting of a repeater/amplifier and four distributedantennas. The total system delay, T_(i) is:T _(i) =T _(offset) +T ₀ +T _(R) +T ₁ +T ₂ +T ₃ +T ₄

During the installation phase of the high gain antenna (if required),repeater (if required) and the distributed antennas, if the system delayis measured at each distributed antenna and the values stored in alocation database, including each antenna identification, and exactphysical location (in three dimensions), then during a location request,all fixed delays will be known, thus the TP value can be determined bysubtracting the fixed, known delay values from Ti, the measured time ofarrival. The TP value can now be used to determine a TOA and or a TDOAvalue in a manner similar to the non-distributed antenna case, thuslocation can be determined based on these TOA/TDOA ranging values.

The required installation methods and procedures required to supportwireless location are illustrated in FIG. 8: Methods and Procedures forDA Installation. By following these methods, the Location Center (LC)will contain a database populated with the necessary data values toperform accurate location estimates within the building containing thedistributed antennas. Table B illustrates typically data element typesand values required in the DA location estimate model database. TableDA-11 below illustrates how a simple TOA location estimate model can beused to determine wireless location in a DA environment. Based on theknown geometry and coverage areas of each DA cell, and the percentage ofmaximum radius, determined by the above classification, it is possibleto construct radius-radius circles of the DA cells. The intersection ofthe three circles (in this case) provides the location estimate. TABLEDA-11 DA Cell Classification and Radius Percentage DA Cell ID Low RangeHigh Range Actual % Max Radius. 1 0 1.96 1.68 88 2 2.46 4.42 3.98 78 47.38 9.34 9.16 91

In order for the TOA and TDOA location calculations to be determined, itis a necessary condition that during distributed antenna installation,the minimum values of the Delay Elements be set to each exceed themaximum practical (i.e., within the coverage area) TP values be at least½ of a PN chip duration (about 500 nanoseconds), to easily allow for theCDMA Data Receivers to be able to correlate between the delay elementvalues and the TP delay values. FIG. 12: DA Delay Spread Ranges,illustrates typical maximum ranging variable delay values (e.g., up to1,960 feet) if 500 nanosecond guard zones (t) are used. If largerranging values are required, then guard zone delays must be increasedproportionally.

FIG. 13: DA Cell Layout and Geometry, illustrates, for DA omnicell sizeswith a radius of about 2,000 feet and guard zones of 500 nanoseconds,that the minimum required cumulative delay values for the delay elementsare: t₂=2.46 microseconds (uS), t₃=4.92 uS, and t₄=7.38 uS,respectively.

It should also be noted that a maximum upper bound exists for themaximum amount of cumulative system propagation delay which can betolerated by the CDMA mobile station. The total delay cannot exceed anamount that would interfere with the next pilot PN offset, orsubstantially delay the scanning time of the search receiver in themobile station. In any case, 30 to 40 microseconds of total delay isacceptable, and would allow for a relatively large number of distributedantenna components to be included, thus no unusual impacts are requiredof the system to accommodate location methods.

By purposefully introducing a relatively large amount of delay in thedistributed antenna delay elements, relative to the maximum permissibleTP delay values, it is possible to utilize the large Delay Elementvalues to uniquely identify the distributed antenna ID, and thus via thedistributed antenna database, to determine the antennas' exact location.Knowing the antenna's location and TP value (last stage of propagationdelay), TOA and TDOA ranging can be achieved, and thus mobile stationlocation within a distributed antenna configuration, can be determined.

FIG. 14: Actual Measurements and Classification, illustrates how CDMAdelay spread measurements are used in a DA configuration to form arelationship with the mobile station location with respect to the DAlocations. Although the CDMA air interface standard only requires thesignal strength and time of arrival of the first useable delay spreadsignal to be reported from the mobile station to the BS, assume herethat the mobile station has the capability to provide the BS, andconsequently the LC, with a list of all peak values of CDMA fingers.

Assume that the mobile station detects and telemeters three CDMA fingerRF measurements, as shown in the table A below, New Message Type DataStructure Content. TABLE A New Message Type Data Structure Content.Signal Strength Delay Time of Arrival −77 dBm 1.68 microseconds −66 3.98−95 9.16

Note that the measurements may be averaged over a sample space of 128individual measurements. Referring now back to FIG. 14, it can be seenthat the first finger is associated with the DA cell-1, range 0 to 1.96microseconds, and DA cell-2, range 2.46 microseconds to 4.42microseconds (uS), and DA cell-4, range 7.38 to 9.34 microseconds. Sincethe DA cell antennas are fixed, with known locations, correlation's canbe derived and established to relate actual measurements with locations.Any one of several location estimating models may be used, using theradius-radius method, or multiple invocations of different modules mayalternatively be used to form a location estimate of the mobile stationwithin the DA environment.

It is now possible to classify the above actual measurements aspropagation delayed signals for the DA cells 1, 2, and 4, since each DAcell delay range is known, and sufficient guard zones exist betweendelay spread ranges to unambiguously classify the measurements, and thusto determine mobile station location. The following table illustrates atypical database containing the classification columns for each DA celland their corresponding location in an x,y plane. TABLE B New MessageType Data Structure Content for Exemplary DA Location Database RecordsDA Cell Location (X, Y) DA Cell Low Range High Range ID in feet) Radius(microseconds) (In microseconds) 1 (0, 0) 1.96 0 1.96 2 (−20, 3000) 1.962.46 4.42 3 (4000, 2800) 1.96 4.92 6.88 4 (1600, 2800) 1.96 7.38 9.34

Translating the actual delay measurements into a percentage of themaximum radius of each cell (i.e., cell 1 radius actual is 88%, cell 2radius actual is 78%, and cell radius 4 actual is 91%) provides wirelesslocation using familiar radius-radius calculations.

Depending upon the combinations of embodiments, the Location Center andGateway may contain from one to three interfaces into the digital PCSnetwork, shown as interfaces X, Y, and Z, in FIG. 24, Location andCTIA/TR45 Network Reference Model. Network interface reference pointsUm, A, Ai, B, C, D and H are part of the Cellular TelecommunicationsIndustry of America (CTIA)/Technical Reference 45 standards, and are notdiscussed further.

Network interface reference point X provides a direct connection to themobile switch center, used for transferring RF measurement signals fromthe mobile station and BS to the LC and for transferring locationcontrol between the LS and mobile station, and between the LC and BS.This interface can be implemented via any number of data communicationscircuit configurations and protocols in current use, such as a T-carrierdata circuit, with DSU/CSUs at each end, using an intranet/internetprotocol suite, such as TCP/IP, RPC messaging, or other middlewaresolutions, such as Pipes, IBM MQ series, world wide web protocols, suchas JAVA/VRML scripts, hypertext markup language (HTML) links, and mayalso include various firewall schemes and data encryption mechanisms,etc., in order to communicate asynchronous messaging among theendpoints, and in particular, in reference to the final distribution ofthe location information to the desired end user.

Network interface reference point Y is used in the embodiment wherein apublic switched telephone network interface is required or desired. Thisinterface is a straightforward method to support location applicationswherein, for example, a mobile station user dials a telephone number inorder to initiate a location request, and could also be used totelemeter RF measurement and location control messages between the LCand the mobile station/BS. Alternatively a timer-initiated processinternal to the LC may be used to start a location request, or via anynumber of events external to the network. Point Y also has the advantageof not requiring a direct connection to a commercial radio mobileservice providers' network elements, thus affording a convenientinterface for use by third party location service providers unrelated tothe commercial radio mobile service provider.

National Scale Wireless Location

By utilizing specific data items used in the Home Location Register inthe Advanced Intelligent Network, it is possible to determine the mobilestation location on a national scale, i.e., location within the contextof a state, and in which city.

Referring now to FIGS. 24 and 25, network interface reference point Z isused in the embodiment wherein a gross location must be determined. Agross location is defined as an area associated with a particular mobileswitch center coverage area. Mobile switch center coverage areas aretypically bounded by a large metropolitan area, such as a city. The HomeLocation Register (HLR) contains gross location information. The Zinterface allows the LC 142 to query the home location register todetermine if the user is in their “home area, or whether the user isroaming to another mobile switch center coverage area, such as anothercity. IS-41 Cellular Radio Telecommunications intersystem operationscommunications protocols provide mechanisms that allow a user to roaminto authorized areas outside of their “home” area.

If the user is roaming in another area, then the LC 142 can use thatinformation to initiate location control messages toward the CDMAnetwork currently hosting the mobile station user. FIG. 25 illustrateshow a user based in Los Angeles, Calif., for example, may roam to a CDMAsystem in New York City, and be “located” within that metropolitan area,through a data communications network and a national Location CenterClearinghouse system.

Signal Processor Subsystem

The signal processing subsystem receives control messages and signalmeasurements and transmits appropriate control messages to the wirelessnetwork via the location applications programming interface referencedearlier, for wireless location purposes. The signal processing subsystemadditionally provides various signal identification, conditioning andpre-processing functions, including buffering, signal typeclassification, signal filtering, message control and routing functionsto the location estimate modules.

There can be several combinations of Delay Spread/Signal Strength setsof measurements made available to the signal processing subsystem 20within the Location Center/System 142, shown in FIG. 3. In some casesthe mobile station 140 may be able to detect up to three or four PilotChannels representing three to four Base Stations, or as few as onePilot Channel, depending upon the environment. Similarly, possibly morethan one BS 122 can detect a mobile station 140 transmitter signal, asevidenced by the provision of cell diversity or soft hand-off in theCDMA standards, and the fact that multiple CMRS' base station equipmentcommonly will overlap coverage areas. For each mobile station 140 or BS122 transmitted signal detected by a receiver group at a station,multiple delayed signals, or “fingers” may be detected and trackedresulting from multipath radio propagation conditions, from a giventransmitter.

In typical spread spectrum diversity CDMA receiver design, the “first”finger represents the most direct, or least delayed multipath signal.Second or possibly third or fourth fingers may also be detected andtracked, assuming the mobile station contains a sufficient number ofdata receivers. Although traditional TOA and TDOA methods would discardsubsequent fingers related to the same transmitted finger, collectionand use of these additional values can prove useful to reduce locationambiguity, and are thus collected by the Signal Processing subsystem inthe Location Center 142.

For each pilot channel detection case, multiple fingers (up to three orfour) may be detected and thus reported to the Location system 142, asshown in FIG. 22 and 23, for dense urban and rural settings,respectively. From the mobile receiver's perspective, a number ofcombinations of measurements could be made available to the LocationCenter. Table SP-1 illustrates the available combinations for three andfour receiver cases, respectively. TABLE SP-1 Nominal CDMA LocationMeasurement Combinations No. of No. of No. of No. of No. of Fingers, BSFingers, BS Fingers, BS Fingers, 4-S No. of No. of BSs Fingers 1-S(first 2-S (second 3-S (third (fourth Receivers detected Detectedstrongest) strongest) strongest) Strongest 3 1 1 1 0 0 0 3 1 2 2 0 0 0 31 3 3 0 0 0 3 2 2 1 1 0 0 3 2 3 2 1 0 0 3 2 3 1 2 0 0 3 3 3 1 1 1 0 4 44 1 1 1 1 4 3 4 1 2 1 0 4 3 4 1 2 1 0 4 3 4 2 1 1 0 4 2 4 3 1 0 0 4 2 42 2 0 0 4 2 4 1 3 0 0 4 1 4 4 0 0 0

The above Table SP-1 scenario assumes that the mobile station design anddata collection structure only permits a 1:1 correspondence to existbetween the number of base stations detected and the number of datareceivers reporting multipath CDMA fingers.

Table SP-1 illustrates the potential combinations of detected CDMAsignals representing multipath fingers and total number of detectablebase station pilot signals in a given location within the radio coveragearea 120. Due to the disperse and near-random nature of CDMA radiosignals and propagation characteristics, traditional TPO/TDOA locationmethods have failed in the past, because the number of signals receivedin different locations are different. In a particularly small urbanarea, say less than 500 square feet, the number of RF signals and theremultipath components may vary by over 100 percent.

FIGS. 18 and 19 illustrate a certain case from a location measurementperspective, of signals received for a three-data receiver and afour-data receiver configuration, in a nominal three sector honeycombbase station configuration. In FIG. 18, a mobile station at location “A”detects base stations 1 b, 5 c, and 4 a. However although a triad ofsignals are received, if varying multipath signals are received from oneor more base stations, then ambiguity can still result. FIG. 19illustrates a mobile station located at position “A”, detecting basestations 1 b, 5 c, 4 a, and 2 c. Although additional information is madeavailable in this second case, traditional hyperbolic combinations takenthree at a time, yield multiple location estimates. In certain cases thelimit of the back-side of a “far-away” sectored antenna can be used todetermine the limit of RF coverage in another base station sector area.FIG. 20 shows that normally a delay spread in sector 1 b would imply arange of a 120 degree solid angle. However by using the known fact thatbase station sector 2 a contains a coverage limit, such negative logiccan be used to further restrict the apparent coverage area in sector 1b, from 120 degrees to approximately 90 degrees as shown in theillustration, in order to locate the mobile station B. Such informationregarding sector 2 a can be determined by collecting the remaining setinformation from mobile station B.

Now consider more practical, less ideal cases. Due to the large capitaloutlay costs associated with providing three or more overlapping basestation coverage signals in every possible location, most practicaldigital PCS deployments result in fewer than three base station pilotchannels being reportable in the majority of location areas, thusresulting in a larger, more amorphous location estimate. FIG. 20 and 21illustrate a typical relative error space wherein a mobile stationdetects only two base station pilot channels, and only one pilotchannel, respectively. This consequence requires a family of locationestimate location modules or models, each firing whenever suitable datahas been presented to a model, thus providing a location estimate to abackend subsystem which resolves ambiguities.

In one embodiment of this invention using backend hypothesis resolution,by utilizing existing knowledge concerning base station coverage areaboundaries (such as via the compilation a RF coverage database—eithervia RF coverage area simulations or field tests), the location errorspace is decreased. Negative logic Venn diagrams can be generated whichdeductively rule out certain location estimate hypotheses.

Base Station Cell site planning tools which utilize antenna gainradiation patterns, environmental clutter, such as buildings, denseforests, terrain heights, etc., can provide reasonable training data tobootstrap the initial operation of the LC.

An example of the types of data typically collected during fieldtests/runs is shown in the following database table SP-2 below: TABLESP-2 Typical CDMA Field Test Measurements Column Position Mobile DataTest Set: Data Type Logged 1 CDMA Time (absolute, from GPS) 2 VehicleSpeed (in mph) 3 Vehicle Latitude (in deg. North) 4 Vehicle Longitude(in deg. East) 5 GPS Source (binary, e.g., GPS or Dead Reckoning) 6 GPSData available indicator (binary states) 7 First BS-Mobile ReceivedPower (in dBm, 1 second averages) 8 Mobile transmit Gain Adjust (in dBm,1 second average) 9 First BS Mobile Rx Pilot E_(c)/I_(o) (dB, 1 secondaverage) 10 First BS Mobile received Frame Counts (integers permeasurement period) 11 Mobile Finger's Average Time Separation (innano/microseconds) 12 Mobile Fingers' Maximum Time Separation (innano/microseconds) 13 Mobile Fingers' Number of Pilots locked (per 1second average) 14 Mobile finger Lock Counts 15 First BS Received FrameCounts 16 First BS Eb/No set Point (in dB, 1 second average) 17 First BScell Rx Eb/No per antenna (in dB, 1 second average) 18 Hand-off State(relative to the First, or connected-to BS) 19 First BS Traffic ChannelGain 20 First BS Power Control Subchannel Gain 21 First BS Reverse Linkfull Frame Error Rate, over 500 frames 22 Forward Link full Frame ErrorRate, over 500 frames 23 First BS Pilot Channel Delay Spread (innanoseconds) 24 Second BS-Ranked Pilot Delay Spread (in nanoseconds) 25Second BS-Ranked Pilot Relative Signal Strength (in dB) 26 ThirdBS-Ranked Pilot Delay Spread 27 Third BS-Ranked Pilot Relative SignalStrength (in dB) 28 Mobile Antenna Identification (in the case of amulti-sectored antenna) 29 Vehicle compass orientation (bearing orheading) 30 Mobile Station Power Class (an integer, 0-7, indicating max.power capabilities of the mobile station transmitter)

Although the forward link mobile station's received relative signalstrength (RRSS_(BS)) of detected nearby base station transmitter signalscan be used directly by the location estimate modules, the basestation's reverse link received relative signal strength (RRSS_(MS)) ofthe detected mobile station transmitter signal must be modified prior tolocation estimate model use, since the mobile station transmitter powerlevel changes nearly continuously, and would thus render relative signalstrength useless for location purposes.

One adjustment variable and one factor value are required by the signalprocessing subsystem: 1.) instantaneous relative power level in dBm(IRPL) of the mobile station transmitter, and 2.) the mobile stationPower Class. By adding the IRPL to the RRSS_(MS), a synthetic relativesignal strength (SRSS_(MS)) of the mobile station 140 signal detected atthe BS 122 is derived, which can be used by location estimate modelanalysis, as shown below:SRSS _(MS) =RRSS _(MS) +IRPL   (in dBm)

SRSS_(MS), a corrected indication of the effective path loss in thereverse direction (mobile station to BS), is now comparable withRRSS_(BS) and can be used to provide a correlation with either distanceor shadow fading because it now accounts for the change of the mobilestation transmitter's power level. The two signals RRSS_(BS) andSRSS_(MS) can now be processed in a variety of ways to achieve a morerobust correlation with distance or shadow fading.

Although Rayleigh fading appears as a generally random noise generator,essentially destroying the correlation value of either RRSS_(BS) orSRSS_(MS) measurements with distance individually, several mathematicaloperations or signal processing functions can be performed on eachmeasurement to derive a more robust relative signal strength value,overcoming the adverse Rayleigh fading effects. Examples includeaveraging, taking the strongest value and weighting the strongest valuewith a greater coefficient than the weaker value, then averaging theresults. This signal processing technique takes advantage of the factthat although a Rayleigh fade may often exist in either the forward orreverse path, it is much less probable that a Rayleigh fade also existsin the reverse or forward path, respectively. A shadow fade however,similarly affects the signal strength in both paths.

At this point a CDMA radio signal direction-independent “net relativesignal strength measurement” is derived which is used to establish acorrelation with either distance or shadow fading, or both. Although theambiguity of either shadow fading or distance cannot be determined,other means can be used in conjunction, such as the fingers of the CDMAdelay spread measurement, and any other TOA/TDOA calculations from othergeographical points. In the case of a mobile station with a certainamount of shadow fading between its BS 122 (FIG. 2), the first finger ofa CDMA delay spread signal is most likely to be a relatively shorterduration than the case where the mobile station 140 and BS 122 areseparated by a greater distance, since shadow fading does not materiallyaffect the arrival time delay of the radio signal.

By performing a small modification in the control electronics of theCDMA base station and mobile station receiver circuitry, it is possibleto provide the signal processing subsystem 20 (reference FIG. 1) withinthe Location system 142 (FIG. 1) with data that exceed the one-to-oneCDMA delay-spread fingers to data receiver correspondence. Suchadditional information, in the form of additional CDMA fingers(additional multipath) and all associated detectable pilot channels,provides new information which is used to enhance to accuracy of theLocation Center's location estimate location estimate modules.

This enhanced capability is provided via a control message, sent fromthe Location system 142 to the mobile switch center 12, and then to thebase station(s) 122 (FIG. 2) in communication with, or in closeproximity with, mobile stations 140 to be located. Two types of locationmeasurement request control messages are needed: one to instruct atarget mobile station 140 (i.e., the mobile station to be located) totelemeter its BS pilot channel measurements back to the primary BS 122and from there to the mobile switch center 112 and then to the locationsystem 142. The second control message is sent from the location system142 to the mobile switch center 112, then to first the primary BS 122,instructing the primary BS' searcher receiver to output (i.e., return tothe initiating request message source) the detected target mobilestation 140 transmitter CDMA pilot channel offset signal and theircorresponding delay spread finger (peak) values and related relativesignal strengths.

The control messages are implemented in standard mobile station 140 andBS 122 CDMA receivers such that all data results from the searchreceiver and multiplexed results from the associated data receivers areavailable for transmission back to the Location Center 142. Appropriatevalue ranges are required regarding mobile station 140 parametersT_ADD_(s), T_DROP_(s), and the ranges and values for the Active,Neighboring and Remaining Pilot sets registers, held within the mobilestation 140 memory. Further mobile station 140 receiver details havebeen discussed above.

In the normal case without any specific multiplexing means to providelocation measurements, exactly how many CDMA pilot channels and delayspread fingers can or should be measured vary according to the number ofdata receivers contained in each mobile station 140.

As a guide, it is preferred that whenever RF characteristics permit, atleast three pilot channels and the strongest first three fingers, arecollected and processed.

From the BS 122 perspective, it is preferred that the strongest firstfour CDMA delay spread fingers and the mobile station power level becollected and sent to the location system 142, for each of preferablythree BSs 122 which can detect the mobile station 140.

Table SP-3 illustrates the resulting extended combinations of BS signals(pilot channels) and finger measurements potentially available, based onthe above preferred conditions. The philosophy is to collect as muchreasonable data as is practical, given the constraints of CDMAreceivers, search times, receiver memory storage and available CPU anddata transmission bandwidth, in order that sufficient orthogonalinformation can be processed to minimize location estimate error. TABLESP-3 Extended CDMA Location Measurement Combinations No. of No. of No.of No. of No. of No. of Fingers, BS Fingers, BS Fingers, BS Fingers, 4-SNo. of BSs Fingers 1-S (first 2-S (second 3-S (third (fourth Receiversdetected Detected strongest) strongest) strongest) Strongest 3 1 1 1 0 00 3 1 2 2 0 0 0 3 1 3 3 0 0 0 3 2 2 1 1 0 0 3 2 3 2 1 0 0 3 2 3 1 2 0 03 2 4 2 2 0 0 3 2 5 2 3 0 0 3 2 5 3 2 0 0 3 2 4 3 1 0 0 3 2 4 1 3 0 0 42 5 4 1 0 0 4 2 5 1 4 0 0 3 3 3 1 1 1 0 3 2 6 3 3 0 0 3 3 3 1 1 1 0 3 34 2 1 1 0 3 3 4 1 2 1 0 3 3 4 1 1 2 0 3 3 5 2 2 1 0 3 3 5 2 1 2 0 3 3 51 2 2 0 3 3 6 2 2 2 0 3 3 6 3 2 1 0 3 3 6 2 3 1 0 3 3 6 1 2 3 0 3 3 6 13 2 0 4 4 4 1 1 1 1 4 4 5 2 1 1 1 4 4 5 1 2 1 1 4 4 5 1 1 2 1 4 4 5 1 11 2 4 4 6 2 2 1 1 4 4 6 2 1 2 1 4 4 6 1 1 2 2 4 4 6 1 2 2 1 4 4 6 1 2 12 4 4 6 2 1 1 2 4 4 7 3 2 1 1 4 4 7 3 1 2 1 4 4 7 2 3 1 1 4 4 7 2 1 3 14 4 7 2 1 1 3 4 4 7 1 3 2 1 4 4 7 1 2 3 1 4 4 7 1 1 2 3 4 4 7 1 1 3 2 44 7 3 1 1 2 4 4 <13 . . . . . . . . . . . .

As can be seen from the table, a much larger combination of measurementsis potentially feasible using the extended data collection capability ofthe CDMA receivers. In the case of the last row shown, additionalcombinations are also possible using a similar scheme of allocating thenumber of CDMA fingers detected at the first or strongest BS, followedby the second strongest base station, then the third strongest basestation, etc.

FIG. 29 illustrates the components of the Signal Processing Subsystem20. The main components consist of the input queue(s) 7, signalclassifier/filter 9, digital signaling processor 17, imaging filters 19,output queue(s) 21, 23, a signal processor database 26 and a signalprocessing controller 15.

Input queue(s) 7 are required in order to stage the rapid acceptance ofa significant amount of RF signal measurement data, used for eitherlocation estimate purposes or to accept autonomous location data. Eachlocation request using fixed base stations may, in one embodiment,contain from 1 to 128 radio frequency measurements from the mobilestation, which translates to approximately 61.44 kilobytes of signalmeasurement data to be collected within 10 seconds and 128 measurementsfrom each of possibly four base stations, or 245.76 kilobytes for allbase stations, for a total of approximately 640 signal measurements fromthe five sources, or 307.2 kilobytes to arrive per mobile stationlocation request in 10 seconds. An input queue storage space is assignedat the moment a location request begins, in order to establish aformatted data structure in persistent store. Depending upon the urgencyof the time required to render a location estimate, fewer or more signalmeasurement samples can be taken and stored in the input queue(s) 7accordingly.

The signal processing subsystem 20 supports a variety of wirelessnetwork signaling measurement capabilities by detecting the capabilitiesof the mobile and base station through messaging structures provided bythe location application programming interface 14 in FIG. 1. Detectionis accomplished in the signal classifier 9 (FIG. 29) by referencing amobile station database table within the signal processor database 26,which provides, given a mobile station identification number, mobilestation revision code, other mobile station characteristics. Similarly,a mobile switch center table 31 provides MSC characteristics andidentifications to the signal classifier/filter 9. The signalclassifier/filter 9 adds additional message header information thatfurther classifies the measurement data which allows the digital signalprocessor and image filter components to select the proper internalprocessing subcomponents to perform operations on the signal measurementdata, for use by the location estimate modules.

Regarding service control point messages autonomously received from theinput queue 7, the signal classifier/filter 9 determines via a signalprocessing database 26 query that the message is to be associated with ahome base station module. Thus appropriate header information is addedto the message, thus enabling the message to pass through the digitalsignal processor 17 unaffected to the output queue 21, and then to therouter/distributor 23. The router/distributor 23 then routes the messageto the HBS module 6 shown in FIG. 1. Those skilled in the art willunderstand that associating location requests from Home Base Stationconfigurations require substantially less data: the mobileidentification number and the associated wireline telephone numbertransmission from the home location register are on the order of lessthan 32 bytes. Consequentially the home base station message type couldbe routed without any digital signal processing.

Output queue(s) 21 are required for similar reasons as input queues 7:relatively large amounts of data must be held in a specific format forfurther location processing by the location estimate modules.

The router and distributor component 23 is responsible to directingspecific signal measurement data types and structures to theirappropriate modules. For example, the HBS module has no use for digitalfiltering structures, whereas the TDOA module would not be able toprocess an HBS response message.

The controller 15 is responsible for staging the movement of data amongthe signal processing subsystem 20 components input queue 7, digitalsignal processor 17, router/distributor 23 and the output queue 21, andto initiate signal measurements within the wireless network, in responsefrom an internet 468 location request message in FIG. 1, via thelocation application programming interface 14.

In addition the controller 15 receives autonomous messages from the MSC, via the location applications programming interface 14 (FIG. 1) orL-API and the input queue 7, whenever a 9-1-1 wireless call isoriginated. The mobile switch center provides this autonomousnotification to the location system as follows: By specifying theappropriate mobile switch center operations and maintenance commands tosurveil calls based on certain digits dialed such as 9-1-1, the locationapplications programming interface 14 (FIG. 1), in communication withthe MSC 112 a and/or 112 b in FIG. 1, receives an autonomousnotification whenever a mobile station user dials 9-1-1. Specifically, abi-directional authorized communications port is configured, usually atthe operations and maintenance subsystem of the MSC 112 a and/or 112 bin FIG. 1, or with their associated network element manager system(s),with a data circuit, such as a DS-1, with the location applicationsprogramming interface 14 in FIG. 1. Next, the “call trace” capability ofthe mobile switch center is activated for the respective communicationsport. The exact implementation of the vendor-specific man-machine orOpen Systems Interface (OSI) commands(s) and their associated datastructures generally vary among MSC vendors, however the trace functionis generally available in various forms, and is required in order tocomply with Federal Bureau of Investigation authorities for wire tappurposes. After the appropriate surveillance commands are established onthe MSC, such 9-1-1 call notifications messages containing the mobilestation identification number (MIN) and, in FCC phase 1 E9-1-1implementations, a pseudo-automatic number identification (a.k.a. pANI)which provides an association with the primary base station in which the9-1-1 caller is in communication, are communicated. In cases where thepANI is known from the onset, the signal processing subsystem 20 avoidsquerying the MSC in question to determine the primary base stationidentification associated with the 9-1-1 mobile station caller.

After the signal processing controller 15 receives the first messagetype, the autonomous notification message from the mobile switch center112 to the location system 142, containing the mobile identificationnumber and optionally the primary base station identification, thecontroller 15 queries the base station table 13 in the signal processordatabase 26 to determine the status and availability of any neighboringbase stations, including those base stations of other CMRS in the area.The definition of neighboring base stations include not only thosewithin a provisionable “hop” based on the cell design reuse factor, butalso includes, in the case of CDMA, results from remaining setinformation autonomously queried to mobile stations, with results storedin the base station table. Remaining set information indicates thatmobile stations can detect other base station (sector) pilot channelswhich may exceed the “hop” distance, yet are nevertheless candidate basestations (or sectors) for wireless location purposes. Although cellularand digital cell design may vary, “hop” distance is usually one or twocell coverage areas away from the primary base station's cell coveragearea.

Having determined a likely set of base stations which may both detectthe mobile station's transmitter signal, as well as to determine the setof likely pilot channels (i.e., base stations and their associatedphysical antenna sectors) detectable by the mobile station in the areasurrounding the primary base station (sector), the controller 15initiates messages to both the mobile station and appropriate basestations (sectors) to perform signal measurements and to return theresults of such measurements to the signal processing system regardingthe mobile station to be located. This step may be accomplished viaseveral interface means. In a first case the controller 15 utilizes, fora given MSC, predetermined storage information in the MSC table 31 todetermine which type of commands, such as man-machine or OSI commandsare needed to request such signal measurements for a given MSC 112 a or112 b in FIG. 1. The controller generates the mobile and base stationsignal measurement commands appropriate for the MSC and passes thecommands via the input queue 7 and the locations application programminginterface 14 in FIG. 1, to the appropriate MSC 112 a and 112 b, usingthe authorized communications port mentioned earlier. In a second casethe controller 15 communicates directly with the base stations asdiscussed above and shown in FIG. 5, Location Center-base stationaccess, multiple CMRS. In this second case, an alternative embodiment isprovided to directly extract the wireless location signal measurementdata from each base station associated with each of the multiple CMRSnetworks having to interface directly with the MSC for signalmeasurement extraction.

Upon receipt of the signal measurements, the signal classifier 9examines location application programming interface-provided messageheader information from the source of the location measurement (forexample, from a fixed BS 122, a mobile station 140, a distributedantenna system 168 or message location data related to a home basestation), provided by the location applications programming interface(L-API 14) via the input queue 7 and determines whether or not devicefilters 17 or image filters 19 are needed, and assesses a relativepriority in processing, such as an emergency versus a backgroundlocation task, in terms of grouping like data associated with a givenlocation request. In the case where multiple signal measurement requestsare outstanding for various base stations, some of which may beassociated with a different CMRS network, an additional signalclassifier function includes sorting and associating the appropriateincoming signal measurements together such that the digital signalprocessor 17 processes related measurements in order to build ensembledata sets. Such ensembles allow for a variety of functions such asaveraging, outlier removal over a time period, and related filteringfunctions, and further prevent association errors from occurring inlocation estimate processing.

Another function of the signal classifier/low pass filter component 9 isto filter information that is not useable, or information that couldintroduce noise or the effect of noise in the location estimate modules.Consequently low pass matching filters are used to match the in-commonsignal processing components to the characteristics of the incomingsignals. Low pass filters match: Mobile Station, base station, CMRS andMSC characteristics, as well as to classify Home Base Station messages.

The signal processing subsystem 20 in FIG. 1 contains a base stationdatabase table 13 (FIG. 29) which captures the maximum number of CDMAdelay spread fingers for a given base station, containing informationstructures as shown in table SP-4 below: TABLE SP-4 Base StationCharacteristics Primary Base Latitude, Pilot BS Maximum StationLongitude, Channel Identifier No. of Identification elevation Offsetcode CDMA Fingers DEN-001 x, y, z 5 CODENABC001 4 DEN-002 p, q, r 25CODENABC002 4 DEN-003 s, t, u 20 CODENABC003 3 DEN-004 a, b, c 15CODENABC004 4 BLD-005 d, e, f 45 COBLDABC005 4

The base station identification code, or CLLI or common language levelidentification code is useful in identifying or relating a human-labeledname descriptor to the Base Station. Latitude, Longitude and elevationvalues are used by other subsystems in the location system forcalibration and estimation purposes. As base stations and/or receivercharacteristics are added, deleted, or changed with respect to thenetwork used for location purposes, this database table must be modifiedto reflect the current network configuration.

Just as an upgraded base station may detect additional CDMA delay spreadsignals, newer or modified mobile stations may detect additional pilotchannels or CDMA delay spread fingers. Additionally different makes andmodels of mobile stations may acquire improved receiver sensitivities,suggesting a greater coverage capability. The table below establishesthe relationships among various mobile station equipment suppliers andcertain technical data relevant to this location invention.

Although not strictly necessary, the MIN can be populated in this tablefrom the PCS Service Provider's Customer Care system during subscriberactivation and fulfillment, and could be changed at deactivation, oranytime the end-user changes mobile stations. Alternatively, since theMIN, manufacturer, model number, and software revision level informationis available during a telephone call, this information could extractedduring the call, and the remaining fields populated dynamically, basedon manufacturers specifications information previously stored in thesignal processing subsystem 20. Default values are used in cases wherethe MIN is not found, or where certain information must be estimated.TABLE SP-5 Mobile Station Characteristics Table Maximum Rec. AllowedMaximum No. Transmit Thermal Mobile Station S/W No. of of Power NoiseIdentification Model Revision CDMA Pilots Class Floor (MIN) ManufacturerNo. Levels Fingers Detectable (Max) (dBm) 3034561234567 Sony 5 R1.0 3 32 −114 3034561234568 Qualcomm 25 R2.01 4 4 4 −115 3034561234569Panasonic 20 R1.1 3 3 5 −113 3034561234570 Fujutshu 15 R2.5 4 4 0 −1163034561234571 Sony 45 R1.1 3 3 7 −115 Default Default Default R1.0 3 3 3−112

A low pass mobile station filter, contained within the signalclassifier/low pass filter 9 of the signal processing subsystem 20, usesthe above table data to perform the following functions: 1) act as a lowpass filter to adjust the nominal assumptions related to the maximumnumber of CDMA fingers, pilots detectable; and 2) to determine thetransmit power class and the receiver thermal noise floor. Given thedetected reverse path signal strength, the required value of SRSS_(MS),a corrected indication of the effective path loss in the reversedirection mobile station to BS), can be calculated based on the SP-5table data contained within the mobile station table 11, in the signalprocessing database 26.

The effects of the maximum Number of CDMA fingers allowed and themaximum number of pilot channels allowed essentially form a low passfilter effect, wherein the least common denominator of characteristicsare used to filter the incoming RF signal measurements such that a onefor one matching occurs. The effect of the Transmit Power Class andreceiver Thermal Noise floor values is to normalize the characteristicsof the incoming RF signals with respect to those RF signals used.

FIG. 4, Location Provisioning from Multiple CMRSs, illustrates a systemarchitecture to enable the customer care systems belonging to differentCMRSs, either on an autonomous or periodic basis, to update aprovisionable signal processing database 26, containing the mobilestation characteristics, in communication with the signalclassifier/filter 9, input queue 7, and the location applicationsprogramming interface for customer care systems (L-API-CCS) 138. Thesignal classifier/filter 9 is in communication with both the input queue7 and the signal processing database 26. In the early stage of alocation request the signal processing subsystem 20 in FIG. 4, willreceive the initiating location request from either an autonomous 9-1-1notification message from a given MSC, or from a location application146 (for example, see FIG. 36), for which mobile station characteristicsabout the target mobile station 140 (FIG. 2) is required. Referring toFIG. 29, a query is made from the signal processing controller 15 to thesignal processing database 26, specifically the mobile station table 11,to determine if the mobile station characteristics associated with theMIN to be located are available in table 11. if the data exists thenthere is no need for the controller 15 to query the wireless network inorder to determine the mobile station characteristics, thus avoidingadditional real-time processing which would otherwise be required acrossthe air interface, in order to determine the mobile station MINcharacteristics. The resulting mobile station information may beprovided either via the signal processing database 26 or alternatively aquery may be performed directly from the signal processing subsystem 20to the MSC in order to determine the mobile station characteristics.

A location application programming interface, L-API-CCS 138 to theappropriate CMRS customer care system provides the mechanism to populateand update the mobile station table 11 within the database 26. TheL-API-CCS 138 contains its own set of separate input and output queuesor similar implementations and security controls to ensure thatprovisioning data is not sent to the incorrect CMRS. The interface 1155a to the customer care system for CMRS-A 1150 a provides an autonomousor periodic notification and response application layer protocol type,consisting of add, delete, change and verify message functions in orderto update the mobile station table 11 within the signal processingdatabase 26, via the controller 15. A similar interface 1155 b is usedto enable provisioning updates to be received from CMRS-B customer caresystem 1150 b.

Although the L-API-CCS application message set may be any protocol typewhich supports the autonomous notification message with positiveacknowledgment type, the T1M1.5 group within the American NationalStandards Institute has defined a good starting point in which theL-API-CCS could be implemented, using the robust OSI TMN X-interface atthe service management layer. The object model defined in Standardsproposal number T1M1.5/96-22R9, Operations Administration, Maintenance,and Provisioning (OAM&P)—Model for Interface Across JurisdictionalBoundaries to Support Electronic Access Service Ordering: InquiryFunction, can be extended to support the L-API-CCS information elementsas required and further discussed below. Other choices in which theL-API-CCS application message set may be implemented include ASCII,binary, or any encrypted message set encoding using the Internetprotocols, such as TCP/IP, simple network management protocol, http,https, and email protocols.

Referring to the digital signal processor (DSP) 17, in communicationwith the signal classifier/LP filter 9, the DSP 17 provides a timeseries expansion method to convert non-HBS data from a format of ansignal measure data ensemble of time-series based radio frequency datameasurements, collected as discrete time-slice samples, to a threedimensional matrix location data value image representation. Othertechniques further filter the resultant image in order to furnish a lessnoisy training and actual data sample to the location estimate modules.

Referring now to digital signal and image filter processing, by way ofexample, a forward-path CDMA mobile station delay spread RF measurementsample is illustrated in FIG. 22, for the mobile station reception ofone sample of transmission signal related to BS-1, located at 16th andStout Streets. In this sample three fingers or groups of RF energy(relative signal strength is indicated along the vertical axis) weredetected. A first CDMA finger was found at a delay of about 3.4microseconds, and relative signal strength of about −80 dBm. A secondfinger was found at a delay of about 5 microseconds, and peak strengthof about −55 dBm, followed by a third finger at 6.5 microseconds and astrength of about −92 dBm. Two other base stations were detected, BS-5and BS-2, along with their respective three CDMA delay spread fingers.

Refer now to the left image shown in FIG. 26: Delay Spread ProfileImage. After 128 samples of data are collected of the delayspread-relative signal strength RF data measurement sample: mobilestation RX for BS-1 and grouped into a Quantization matrix, where rowsconstitute relative signal strength intervals and columns define delayintervals. As each measurement row, column pair (which could berepresented as a complex number or Cartesian point pair) is added totheir respective values to generate a Z direction of frequency ofrecurring measurement value pairs or a density recurrence function. Bynext applying a grid function to each x, y, and z value, athree-dimensional surface grid is generated, which represents a locationdata value or unique print of that 128-sample measurement. FIG. 28illustrates the result of image generation when a number of datasamples, or an ensemble of signal strength, delay pairs of values areadded within a given bin area or matrix, to thus create a type ofthree-dimensional image, representing a particular RF signaling behaviorat a given location.

Refer now to the right image shown in FIG. 26. In the general case wherea mobile station is located in an environment with varied clutterpatterns, such as terrain undulations, unique man-made structuregeometries (thus creating varied multipath signal behaviors), such as acity or suburb, although the first CDMA delay spread finger may be thesame value for a fixed distance between the mobile station and BSantennas, as the mobile station moves across such an arc, differentfinger-data are measured. In the right image for the defined BS antennasector, location classes, or squares numbered one through seven, areshown across a particular range of line of position (LOP).

A traditional TOA/TDOA ranging method between a given BS and mobilestation only provides a range along the arc, thus introducing ambiguityerror. However a unique three dimensional image can be used in thismethod to specifically identify, with recurring probability, aparticular unique location class along the same Line Of Position, aslong as the multipath is unique by position but generally repeatable,thus establishing a method of not only ranging, but also of completelatitude, longitude location estimation in a Cartesian space. In otherwords, the unique shape of the “mountain image” enables a correspondenceto a given unique location class along a line of position, therebyeliminating traditional ambiguity error.

Although man-made external sources of interference, Rayleigh fades,adjacent and co-channel interference, and variable clutter, such asmoving traffic introduce unpredictability (thus no “mountain image”would ever be exactly alike), three basic types of filtering methods canbe used to reduce matching/comparison error from a training case to alocation request case: 1.) select only the strongest signals from theforward path (BS to mobile station) and reverse path (mobile station toBS), 2.) Convolute the forward path 128 sample image with the reversepath 128 sample image, and 3.) process all image samples through variousdigital image filters to discard noise components.

The strongest signal technique has been discussed previously in the datafilter section. FIG. 27: Convolution of Forward and Reverse Images,illustrates one method that essentially nulls noise completely, even ifstrong and recurring, as long as that same noise characteristic does notoccur in the opposite path.

The third technique of processing CDMA delay spread profile imagesthrough various digital image filters, provides a resultant “imageenhancement” in the sense of providing a more stable pattern recognitionparadigm to the neural net location estimate model. For example, imagehistogram equalization can be used, as illustrated in FIG. 30 (beforeequalization) and 31 (after equalization) to rearrange the images'intensity values, or density recurrence values, so that the image'scumulative histogram is approximately linear.

Other methods which can be used to compensate for a concentratedhistogram include: 1) Input Cropping, 2) Output Cropping and 3) GammaCorrection. Equalization and input cropping can provide particularlystriking benefits to a CDMA delay spread profile image. FIGS. 32 and 33illustrate the three dimensional grid images of the before and afterinput cropping filter example. As shown in FIG. 33, input croppingremoves a large percentage of random signal characteristics that arenon-recurring.

Other filters and/or filter combinations can be used to help distinguishbetween stationary and variable clutter affecting multipath signals. Forexample, it is desirable to reject multipath fingers associated withvariable clutter, since over a period of a few minutes such fingerswould not likely recur. Further filtering can be used to removerecurring (at least during the sample period), and possibly strong butnarrow “pencils” of RF energy. A narrow pencil image component could berepresented by a near perfect reflective surface, such as a nearby metalpanel truck stopped at a traffic light.

On the other hand, stationary clutter objects, such as concrete andglass building surfaces, adsorb some radiation before continuing with areflected ray at some delay. Such stationary clutter-affected CDMAfingers are more likely to pass a 4×4 neighbor Median filter as well asa 40 to 50 percent Input Crop filter, and are thus more suited to neuralnet pattern recognition. FIG. 33 illustrate five “pencils” of CDMAfinger energy that passed a simple 50 percent Input Crop filter.However, as shown in FIG. 34 when subjected to a 4×4 neighbor Medianfilter and 40 percent clipping, all five pencil-shaped fingers have beendeleted. FIG. 35 illustrates the further simplified result of a 50percent cropping and 4×4 neighbor median filtering. Other filteringmethods include custom linear filtering, adaptive (Weiner) filtering,and custom nonlinear filtering.

The DSP 17 may provide data ensemble results, such as extracting theshortest time delay with a detectable relative signal strength, to therouter/distributor 23, or alternatively results may be processed via oneor more image filters 19, with subsequent transmission to therouter/distributor 23. The router/distributor 23 examines the processedmessage data from the DSP 17 and stores routing and distributioninformation in the message header router/distributor 23 then forwardsthe data messages to the output queue 21, for subsequent queuing thentransmission to the appropriate location estimators DA module 10,TOA(TDOA module 8 or the HBS module 6, in FIG. 1.

Home Base Station Module

Upon receiving a message from the Data Capture Gateway or the signalprocessing subsystem 20, the HBS location estimate model examines a HomeBase Station Table which defines relationships among a wireless MIN, andwireline telephone number, characteristics of the HBSD, and thepossibility to use various signal types in order to further define thelocation within the address area of the fixed location HBSD. Thefollowing table, populated by the commercial mobile radio serviceprovider at HBSD installation time, is used by the HBS model todetermine location whenever the mobile station 140 is located withincommunication range of the HBSD: TABLE HBS-1 HBSD Characteristics HBSDlocation CDMA Wireline Wireless Latitude, Strength/Delay MIN MIN HBSDModel Longitude Fixed HBSD Location Measurements? 3035561234 3035661299Sony Qx-9000, Rev. 52.619488 N, 727 Magnolia Drive, No 1.1 112.4197601 WBoulder, CO 3035561236 3035661200 Panasonic PF-130, 52.645488 N, 1401Digit Drive, Yes Rev. 5.0 112.4197601 W Boulder, CO 30355612363035661240 Panasonic PF-130, 52.779488 N, 1698 Folsom St., No Rev. 3.4112.4197601 W Boulder, CO. 3035561284 3035661205 Panasonic PF-180,51.619488 N, 990 Nutcracker Dr., NO Rev. 5.0 111.9197601 W Niwot, CO.3035561224 3035661266 Panasonic PF-5000, 52.619558 N, 5606 BismarkCircle, Yes Rev. 1.0 112.4197601 W Denver, CO . . . . . . . . . . . . .. .

In the event RF signals are available for telemetry from the HBSD to thelocation system, such information may be solicited from the locationsystem to the HBSD, in the form of a request/response message scheme,using for example, a data-under-voice technique. In such cases the SSPprovides a data connection with the location system 142 via the PSTN.The home base station may interact with the mobile station in the samemanner as a cordless telephone transceiver interacts with a cordlesstelephone, when the mobile station is within an acceptable range.

The HBS module 6 in FIG. 1 outputs the Latitude and Longitude locationestimates to either the PSTN 124 or to the Internet 468, depending uponthe source of the originating location request.

Distributed Antenna Module

Upon receipt of one or more data ensemble messages from the signalprocessing subsystem 20 in FIG. 1, the distributed antenna (DA) module10 queries a previously populated distributed antenna database todetermine the locations of distributed antennas associated with themeasured DA antenna “pilot delays” so that the detected signalmeasurement delay signal values received from the mobile stationreceivers and base station receivers can be input to the TOA/TDOAmodule. The TOA/TDOA module then utilizes the radius-radius method, ortime difference method, in order to provide location estimates withinthe building or area containing the distributed antennas.

Daisey Chaining Base Stations

As a practical matter it may be necessary in some network conditions toadd base stations in areas to permit improved estimates to be achievedin wireless location. An aspect in this invention includes daisychaining communication circuits or transport facilities between or amongbase stations, in order to simplify the installation and operation ofsuch base stations. Base stations normally communicate with the mobileswitch center using T-carrier transport facilities, in order to carryvoice and data bearer traffic, and to transport bi-directional controlsignals. However for various economic or other reasons it may not bejustifiable to install such transport facilities. At the base station,by essentially originating a plurality of mobile telephone calls usingthe data communications option, and terminating such calls at the mobileswitch center appropriately, the outputs of the base station transportmultiplex circuits are re-directed into the data communication circuitsnormally intended for use by mobile stations in establishing a datacircuit communication call to the network. Circuits at the mobile switchcenter used to terminate these data calls, redirect the communication tothose circuits normally used to terminate the T-carrier facilities fromthe base stations. In this manner, existing wireless channels can beused to provide transport via this daisy-chaining method between certainbase stations and the mobile switch center, thus simplifyingconnectivity in cases where the installation of transport facilitieswould either be impossible or impractical.

Distance First Order Module (TOA/TDOA)

Particular distinctions over the current state of the art includeutilizing essentially the native electronics, antennas and standards,and opposed to overlay solutions, supervisor functions which control ahybrid set of techniques, including Time Of Arrival (TOA), TimeDifference of Arrival (TDOA) in both the forward and reverse paths,pilot signal strengths, power control, mobile stations (mobile station)state conditions, stochastic features of environmental clutter,multipath detection and mitigation, and robustness, supporting a varietyof conditions including degraded/faulty equipment, distributed and SMARTantennas, various registration modes, and various call processingconditions such as soft, hard and idle hand-off conditions, locationduring the idle state, traffic-bearing states, and location during casesof severe multipath, such as that experienced in urban canyonenvironments, as well as location in suburban and rural cases.

Since each base station is required to emit a constant signal-strengthpilot pseudo-noise (PN) sequence on the forward link channel identifieduniquely in a network system by a pilot sequence offset and frequencyassignment, it is possible to use the pilot channels of active,candidate, neighboring and remaining sets of pilots, associated withneighboring base stations, stored in the mobile station, for TOA andTDOA measurements performed by the mobile station.

Based on the arrival time measurement estimates and the speed ofpropagation, ranges or range differences between the base stations andthe mobile station can be calculated. TOA and/or TDOA measurements canthen be input to either the radius-radius multilateration or the timedifference multilateration algorithms.

By utilizing the known base station positions, location of the mobilestation can be determined. Since measurements and base station positionscan be sent either to the network or the mobile station, location can bedetermined in either entity.

Since not all measurements can provide accurate location results at alltimes and conditions, a variety of supervisory logic processes can beinvoked to resolve or litigate the problem area.

As those familiar with the EIA/TIA IS-95 and T1P1/JTC CDMA standardsspecifications know, mobile station call processing consists of fourstates:

-   -   1. Initialization State—where the mobile station selects and        acquires a system, a network, and timing information. This state        consists of four substates: System Determination, Pilot Channel        Acquisit/on, Sync Channel Acquisition, and Timing Change        Substate;    -   2. Idle State—where the mobile station monitors messages on the        Paging Channel, and supports procedures such as Message        Acknowledgment, nine modes of Registration, Idle Hand-off, Pilot        Search, and response to Overhead Information, such as System and        Access Parameters (which include BS Latitude and Longitude),        mobile station Message Transmission Operation (i.e., Data Burst)        and Neighboring List messages;    -   3. System Access State—where the mobile station sends messages        to the base station on the Access Channel. This state consists        of six substates: Update Overhead, Origination Attempt, Page        Response, mobile station Order/Message Response, Registration        Access; Message Transmission Operation/Data Burst);    -   4. Mobile station Control on the Traffic Channel State—where the        mobile station communicates with the primary base station using        the forward and Reverse Traffic Channels. This state consists of        five substates: TC initialization, Waiting for Order, Waiting        for mobile station Answer, Conversation (which includes hand-off        procedures and earliest arriving usable multipath components of        pilots), and Release.

At power-up an IS-95 or T1P1PCS CDMA compliant mobile station entersInitialization State, as described in IS-95, section 6.6.1. During theSystem Determination substate, the mobile station refers to its internalmemory to acquire preferences for system carrier (A or B), or thepreferred carrier at 1.8-2.0 GHz, and for other types of service,including advanced mobile phone service, or AMPS, as well as narrow bandadvanced mobile phone service, or NAMPS.

A CDMA-preferred mobile station then transfers to the Pilot AcquisitionSubstate. The mobile station tunes to the CDMA Channel number equal toCDMACH_(s) then sets its Walsh code (always W0) for the Pilot channelwhere it begins searching for pilot energy, in terms of energy per bit,per spectral density.

Once a sufficiently strong (as defined by the T_ADD threshold parameter)pilot channel has been identified within T_(20m) seconds, the mobilestation enters the Sync Channel Acqusition Substate, where the mobilestation receives a Sync channel Message that includes, among otherinformation, system time and the unique PN offset index for thatparticular BS. In the Timing Change substate, the mobile station adjustsits internal timing to match the BS's CDMA system time. At thecompletion of the Timing Change substate, the mobile station iscompletely synchronized to the CDMA system's BS time.

After satisfactory synchronization the mobile station then enters thestable Idle State, where the paging channel begins to be monitored.

At this point at least two alternatives are possible:

-   -   1. Perform Location determination without consumption of        user-perceived air time via the introduction of a new call        processing state, or    -   2. Perform Location determination via the traffic channel        (requires air time)

In cases where Distributed Antennas (DAs), and/or Home Base Stations(HBS) are used, each location of these devices can be sent to the mobilestation. There are at least three format-types possible in conveyingthis type of location information in the GeoLocation Message. First, aunique identifier can be assigned to each DA/HBS, such as a fullydistinguished name. An example of location information could be: Withinthe USA, State of Colorado, city of Denver, with Service Provider xyz,BS ID 129, Distributed Antenna number 8. Or more compactly, the locationstring is structured as, “USA.CO.DEN.xyz.129.DA8”. Secondly, aneasy-to-understand human style data message can be sent, such as, “Youare near the 30th floor of the Sears Tower building”. Third, data valuesfor Latitude, Longitude, and possibly altitude and accuracy could besent from the BS or Location Center to the mobile station/LU. In orderto be most easily useful to and end-user, in the first and third cases,a database would be needed within the mobile station or a PersonalDigital Assistant device, which performs a translation of numerical datainto a form useful for human understanding.

The mobile station thus maintains a list of location pilot offsets,where the list is ranked based on a weighted combination of receivedsignal energy and BS location. The mobile station selects the bestcandidate BSs for location estimate purposes, which may be slightlydifferent from the Active, candidate and remaining lists.

Additionally the mobile station may send a Data_Burst message back tothe BS or Location Center, informing that no other Pilot Channels weredetected. This “negative” Venn diagram information may be useful withvarious heuristics for location estimate deduction, for example, to notewhere the mobile station is not located.

It is the difference of system time values (as opposed to their absolutevalues) that is important. Note that for purposes of location, anycommunication back to a BS 122 would require re-synchronizing onto thatBS's system time. Although not specified in either IS-95 or T1P1/JTC'sPCS CDMA standards, most mobile station manufacturers build correlatorswith resolutions of approximately ⅛ PN chip, which is about 125nanoseconds (nS). A location equipped mobile station will provide ±125nS. accuracy, which is about ±125 feet.

The mobile station or location entity can process the arrival timeestimates in at least two ways. first the mobile station may differencethe measurements (preferred) to form time-difference-of-arrivals (TDOA);or second, the mobile station may determine absolute time-of-arrival(TOA) by solving for the clock bias between the mobile station and otherCDMA system time reports. TOA requires very well calibrated BS systemclocks among each other.

The following procedure illustrates significant capabilities hidden inthe CDMA standards, which provide a substantial enabling base with whichto provide the measurements and data for this inventions' locationmethods.

First the BS sends the Neighbor List Update Message, containing acomplete list of the neighboring pilot PN sequence offset indices (i.e.,via the NGHBR_PN field) associated with candidate BSs in the area, withwhich the mobile station could possibly scan for detecting usableearliest arriving neighboring useable BS multipath components. This listshould typically be a complete list, as opposed to the presumedcandidate subset. If the mobile station is not already in theTraffic/Conversation State, it could invoke this state by calling adialable telephone number in the network, e.g., a designed “Quiet Line”This approach also allows a billing record to be generated according toroutine wireless telephony practice. If the network is to determinelocation, then the network pages the mobile station 140, connecting themobile station to a Quiet Line/Voice message upon mobile station answer.Note that it may be desirable to suppress the mobile station ringersounding for certain location applications. Other methods may also bepossible.

During installation, each BS 122 in a particular area is provisionedwith the locations of all possible neighboring BSs in its area. The BSs122 use this information to populate a list of all Latitudes andLongitudes which can be sent to the LUs, using the Neighbor List Updatemessage. Second, assuming that the mobile station does not currentlyhave this data or if unknown, then the BS shall send a series of MobileStation Registered Messages, each message containing the latitude andLongitude values (i.e., the BASE_LAT and BASE_LONG fields) associatedwith a neighboring BS pilot PN offset sent with the first message. Notethat the constants N_(6m), Supported Traffic Channel Candidate ActiveSet size, normally set to 6, and N_(7m), Supported Traffic ChannelCandidate Set size, normally set to 5, and N_(8m), the Minimum SupportedNeighbor Set size, normally set to 20, should be sufficient for mostlocation purposes, however these constants could be changed if the needarises.

Third, the BS saves the current T_ADD and T_DROP values in the BSmemory, associated with the In-Traffic LU, and sends the In-TrafficSystem Parameters Message, which includes reduced T_ADD and T_DROPparameter values, useable for location purposes. The value for T_ADDwould typically be set to a value near the lower end of the IS-98specification, possibly below the 80 dB dynamic range requirement, closeto (but not including) the thermal noise power level of the LU receiver.Note that if the LU is using restricted battery, e.g., a portable, thenthe time for keeping T_ADD and T_DROP at a low value for locationestimates purposes, should be kept short to delay adverse consequences,such as increased current drain and noise.

Reduced T_ADD and T_DROP values sent to the mobile station will causethe LU to scan all conceivable neighboring BS pilots provided to it bythe BS, and to measure the strengths of each received pilot, and todetermine the pilot arrival time for each pilot offset. Note that thesignal strengths now measured may not be sufficient for carryingtraffic, but may be sufficient for location purposes.

Assuming the network is to determine location, then the mobile stationreports the arrival time, PILOT_ARRIVAL, for each pilot reported to thebase station. According to the standard the arrival time is measuredrelative to the mobile station's time reference (which was previouslydetermined from the active BS), in units of PN chips ( 1/2288)microseconds, or about 814 nanoseconds, as follows:PILOT_PN-PHASE=(PILOT_ARRIVAL+(64×PILOT_PN))mod 2¹⁵,

where PILOT_PN is the PN sequence offset index of the pilot associatedwith the BS pilot indices in the neighbor list.

In order to achieve location accuracy estimates on the order of a fewhundred feet (or nanoseconds) a higher resolution than 1 PN chip isrequired. Although not specified directly in IS-95, most mobilemanufacturers use correlators with resolutions of approximately ⅛ PNchip, or about 102 nS (suggesting that if no other systemic errors arepresent, about 102 feet of error is expected). Note that the searchwindow size SRCH_WI_A, for each pilot may need to be increased if thereare substantial delays experienced from the environment. It is desirablefor the mobile station to report the second and third arrival time (orthe second and third fingers), and their relative signal strengths,corresponding to each detectable Pilot Channel.

If more than one PILOT_ARRIVAL is available then a basic TDOAmultilateration algorithm may be invoked, at either the LU, or thenetwork. In the network case, the active BS 122 must send a PilotRequest Order for Pilot Measurement Request Order (ORDER code 010001),which causes the mobile station 140 to forward its measurements to theBS (and consequently the network, as appropriate).

At this point a minimally sufficient number of measurements areavailable to perform a location estimate. Thus the BS should restore theoriginal T_ADD and T_DROP values (previously saved in the BS memory) tothe mobile station, via the In-Traffic System Parameters Message.

Additional information may be desirable, such as the active BS' TOAmeasurement, as well as associated BS measurements of the mobilestation's TOA to their BS location. This added information may be sentto the mobile station if the mobile station is to perform location, viathe Data Burst Message on the Forward Traffic Channel. Since 26combinations of data burst types have been reserved for future use inthe standard, dedication of several combinations could be used totelemeter location-related data. In cases where duplicate ranging orother information is available, various supervisor techniques mentionedelsewhere in this document, could be used to refine the locationestimate.

Once the location estimate has been performed, any number of means couldbe used to provide the results to the end user.

The IS-95 and J-STD-008 CDMA specifications require that BSs should besynchronized to within ±3 microseconds of CDMA system time and shall besynchronized to within ±10 microseconds. This invention disclosuremethod assumes the cost of GPS receivers is relatively small, thus timecalibration at a more precise calibration level at each location BS isrecommended to be used by using the very accurate GPS time parameters.Preferably the absolute error deviation among surrounding or neighboringbase stations should be less than 800 nanoseconds, however in most casesthis should not be a fixed requirement, but rather a preference. Incases where absolute BS timing is prohibitively expensive, then the“Forced Hand-off” method discussed below can be used to overcome thepreferred, or strict absolute BS timing requirements.

Three methods have been currently identified. Some of these techniquesapply to other air interface types as well.

-   -   1. Use the first finger at BS (Absolute Ranging), and if        detectable, invoke a “Forced Hand-off” between the mobile        station and a neighboring BS, for a time sufficient to complete        signal measurements between a mobile station transmitter and a        BS receiver, and if possible, between a BS transmitter and a        mobile station receiver, which gives access to as many BS's as        can be detected either by the mobile station receiver or the        surrounding BS receivers.    -   2. Use the first finger at mobile station (Differential Ranging)        to obtain differential time readings of pilot channel from        mobile station    -   3. Use the Pilot Power Level Measurements and Ground Clutter        (Stochastic information)

Now in the general case where three or more BSs can either determineTDOA and/or the mobile station can telemeter such data to the locationentity within the network, repeat this method for BS₂ and BS₃, and BS₃an BS₁, in order to determine the remaining curves, thus yieldinglocation within a 2D space. In the case of 3D geometry (such as amulti-story building with multi-floor pico BS cells), the process mustbe repeated a fourth time in order to determine altitude.

MATLAB MathWorks code to implement the above algorithms follows:

clear;hold off;

j=sqrt(−1);

step_size=0.03;

# Set up BS variables

theta=pi/3* ones(3,1);

D=10*ones(3,1);

z(1)=0;

z(2)=D(1);

z(3)=D(3)*exp(−j*theta(1));

# Define the distance parameters

d=[0 6.4-6.8]′;

location 1=[ ];

location 2=[ ];

location 3=[ ];

# Iterate and solve for the location with respect to the first BS (at(0,0))

t2=−pi:0.05:0.05;

for t1=−pi/3:0.05:0.05,

t1=t1+0.001;

r1=1./(exp(j*t1)−exp(j*t2)).*(D(1)−d(1)*exp(j*t2));

r2=1./(exp(j*t1)−exp(j*t2)).*(D(1)−d(1)*exp(j*t1));

temp=arg(r1);

index=find(abs(temp)==min(abs(temp)));

location1=[location1;r1(index)*exp(j*t1)];

end;

for t1=−pi/3:0.05:0.05

t1=t1+0.001;

r1=1./(exp(j*t1)−exp(j*t2)).*(D(2)−d(2)*exp(j*t2));

r2=1./(exp(j*t1)−exp(j*t2)).*(D(2)−d(2)*exp(j*t1));

temp arg(r1);

index=find(abs(temp)==min(abs(temp)));

location2=[location2;r1(index)*exp(j*t1)];

end;

for t1=−pi/3:0.05:0.05

t1=t1+0.001;

r1=1./(exp(j*t1)−exp(j*t2)).*(D(1)−d(3)*exp(j*t2));

r2=1./(exp(j*t1)−exp(j*t2)).*(D(1)−d(3)*exp(j*t1));

temp arg(r1);

index find(abs(temp)==min(abs(temp)));

location3=[location3;r1(index)*exp(j*t1)];

end;

location2=location2*exp(j*arg(z(3)−z(2)))+z(2);

location3=location3*exp(j*arg(z(1)−z(3)))+z(3);

set yrange [−10:1 ];

set xrange [−1:11 ];

plot([z;z(1)])

hold on

plot(location1)

plot(location2)

plot(location3)

Wireless Location Data Collection

It is worthwhile to discuss techniques for both obtaining the initialcollection of verified location data, as well as how additional locationdata can be obtained for updating the data in this data base in astraightforward cost-effective manner.

Regarding both the obtaining of the initial collection of verifiedlocation data as well as gathering data updates, it is believed thatsome of this data can be obtained from the initial and continuedengineering of the base station infrastructure by the wireless telephonyservice provider(s) in the radio coverage area. Additional verifiedlocation data can be obtained by trained technicians driving and/orwalking certain areas and periodically, at each of a plurality oflocations: (a) determining a location estimate (using, for example, GPSif possible and/or offsets from GPS readings); and (b) using an mobilestation 140 at the location to generate location data communication withthe wireless base station infrastructure.

Alternatively, it is a novel aspect of the present invention that astraightforward method and system for gathering verified location datahas been discovered, wherein a conventional mobile station 140 can beused without any additional electronics or circuit modifications. Oneembodiment of this method and system utilizes the personnel ofbusinesses that travel predetermined routes through the radio coveragearea (e.g., a delivery and/or pickup service) to generate such datausing a conventional mobile station 140 while traversing their routesthrough the radio coverage area. One example of such personnel is thepostal workers, and in particular, the mail carriers havingpredetermined (likely repetitive) routes for mail pickup and/or deliveryat predetermined sites (denoted hereinafter as “mail pickup/deliverysites” or simply “mail sites”). By having such mail carriers each carrya conventional mobile station 140 and periodically generate locationdata communication with the wireless base station infrastructure at mailsites along their routes, additional verified location data can be addedto a Location Data Base (not shown) cost effectively.

To describe how this can be performed, a brief description of furtherfeatures available in a typical mobile station 140 is needed. At leastsome modules of mobile station 140 have the following capabilities:

(27.2.1) a unique mobile station 140 identification number; in fact,every mobile station 140 must have such a number (its telephone number);

(27.2.2) the mobile station 140 has a display and a display memory forpresenting stored data records having telephone numbers and related datato a user. Further, some portion of each data record is annotation andsome portion is able to be transmitted to the wireless base stationnetwork. In particular, the mobile station 140 is able to store andrecall data records of sufficient size such that each data record mayinclude the following information for a corresponding mailpickup/delivery site along a mail route: (a) an address or other textualdescription data (e.g., an English-like description) of the mailpickup/delivery site; (b) a predetermined telephone number; and (c) anumerical code (denoted the “site code” hereinafter) associated with themail pickup/delivery site, wherein the site code is at least uniquewithin a set of site codes corresponding to the mail sites on the mailroute. In one embodiment, the memory may store 99 or more such datarecords, and the display is scrollable through the data records;

(27.2.3 ) the mobile station 140 can have its display memory updatedfrom either an RS232 port residing on the mobile station, or from anover-the-air activation capability of the wireless network;

(27.2.4) the mobile station 140 has a pause feature, wherein a telephonenumber can be dialed, and after some predetermined number of seconds,additional predetermined data can be transmitted either throughadditional explicit user request (e.g., a “hard pause”), orautomatically (e.g., a “soft pause”). Moreover, the additionalpredetermined data can reside in the display memory.

Assuming these features, the following steps can be performed foracquiring additional verified location data:

(27.3.1) For (at least some of the) postal carriers having predeterminedroutes of addresses or locations visited, the postal carriers are eachprovided with an mobile station 140 having the capabilities described in(27.2.1) through (27.2.4) above, wherein the memory in each providedmobile station has a corresponding list of data records for theaddresses visited on the route of the postal carrier having the mobilestation. Moreover, each such list has the data records in the samesequence as the postal carrier visits the corresponding mail sites, andeach data record includes the information as in (27.2.2) for acorresponding mail site the postal carrier visits on his/her mail route.More precisely, each of the data records has: (a) a description of theaddress or location of its corresponding mail pickup/delivery site, (b)a telephone number for dialing a data collection system for the locationcenter 142 (or, alternatively, a reference to a memory area in themobile station having this telephone number since it is likely to be thesame number for most data records), and (c) a site code for the mailpickup/delivery site that is to be transmitted after a predeterminedsoft pause time-out. Note that the corresponding list of data recordsfor a particular postal route may be downloaded from, for example, acomputer at a post office (via the RS232 port of the mobile station140), or alternatively, the list may be provided to the mobile station140 by an over-the-air activation. Further, there are variousembodiments of over-the-air activation that may be utilized by thepresent invention. In one embodiment, the postal carrier dials aparticular telephone number associated with data collection system andidentifies both him/herself by his/her personal identification number(PIN), and the postal route (via a route identifying code).Subsequently, the mail pickup and delivery sites along the identifiedroute are downloaded into the memory of the mobile station 140 viawireless signals to the mobile station 140. However, additionalover-the-air techniques are also within the scope of the presentinvention such as:

-   -   (a) If the postal carrier's route is already associated with the        carrier's PIN for over-the-air activation, then the carrier may        only need to enter his/her PIN.    -   (b) If the mobile station 140 is already associated with a        particular route, then the carrier may only need to activate the        mobile station 140, or alternatively, enter his/her PIN for        obtaining an over-the-air download of the route.    -   (c) Regardless of how the initial download of mail sites is        provided to the mobile station 140, it is also an aspect of the        present invention that if there are more mail sites on a route        than there is sufficient memory to store corresponding data        records in the mobile station, then the data records may be        downloaded in successive segments. For example, if there are 150        mail sites on a particular route and storage for only 99 data        records in the mobile station, then in one embodiment, a first        segment of 98 data records for the first 98 mail pickup/delivery        sites on the route are downloaded together with a 99^(th) data        record for transmitting an encoding requesting a download of the        next 52 data records for the remaining mail sites.        (Alternatively, the data collection system may monitor mobile        station 140 requests and automatically detect the last location        capture request of a downloaded segment, and subsequently        automatically download the next segment of mail site data        records). Accordingly, when the data records of the first        segment have been utilized, a second segment may be downloaded        into the mobile station 140. Moreover, at the end of the last        segment, the data collection system may cause the first segment        for the route to be automatically downloaded into the mobile        station 140 in preparation for the next traversal of the route.

(27.3.2) Given that a download into the mobile station 140 of (at leasta portion of) the data for a postal route has occurred, the postalcarrier traversing the route then iteratively scrolls to the next datarecord on the list stored in the mobile station as he/she visits eachcorresponding mail pickup/delivery site, and activates the correspondingdata record. That is, the following steps are performed at each mailpickup/delivery site:

-   -   (a) As the postal carrier arrives at each mail pickup/delivery        site, he or she checks the scrollable mobile station 140 display        to assure that the address or location of the mail        pickup/delivery site is described by the data record in the        portion of the mobile station display for activating associated        data record instructions.    -   (b) The postal carrier then merely presses a button (typically a        “send” button) on the mobile station 140 for concurrently        dialing the telephone number of the data collection system, and        initiating the timer for the soft pause (in the mobile station        140) associated with the site code for the mail pickup/delivery        site currently being visited.    -   (c) Given that the soft pause is of sufficient length to allow        for the data collection system call to be setup, the mobile        station 140 then transmits the site code for the present mail        pickup/delivery site.    -   (d) Upon receiving the telephone number of the mobile station        140 (via automatic number identification (AIN)), and the site        code, the data collection system then performs the following        steps:        -   (d1) A retrieval of an identifier identifying the route            (route id). Note this may be accomplished by using the            telephone number of the mobile station. That is, when the            data collection system first detects that the mobile station            140 is to be used on a particular route, the telephone            number of the mobile station and the route id may be            associated in a data base so that the route id can be            retrieved using the telephone number of the mobile station.        -   (d2) A retrieval of a location representation (e.g.,            latitude, longitude, and possibly height) of the mail            pickup/delivery site identified by the combination of the            route id and the site code is performed by accessing a data            base having, for each mail site, the following associated            data items: the route id for the mail site, the site code,            the mail site address (or location description), and the            mail site location representation (e.g., latitude,            longitude, possibly height).        -   (d3) A request to the location center 142 is issued            indicating that the location data for the mobile station 140            (resulting from, e.g., the call being maintained between the            mobile station and the data collection system) is to be            retrieved from the wireless network, temporarily saved, and            a location estimate for the mobile station is to be            performed. Accordingly, the data collection system request            to the location center 142 the following:            -   (i) the telephone number of the mobile station 140;            -   (ii) the retrieved location of the mobile station 140                according to the route id and site code;            -   (iii) a request for the location center 142 to perform a                location estimate on the mobile station 140 and return                the location estimate to the data collection system;            -   (iv) a request that the location center 142 retain the                location for the mobile station 140 and associate with                it the location of the mobile station 140 received from                the data collection system.

Regarding step (iii), the location estimate may also include the stepstemporarily increasing the mobile station transmitter power level

(27.3.3) Subsequently, given that the location center 142 performs asrequested, when the data collection system receives the mobile station140 location estimate from the location center, the data collectionsystem first associates the returned mobile station location estimatewith the corresponding data collection system information regarding themobile station, and secondly, performs “reasonability” tests on theinformation received from the mobile station 140 for detecting,filtering and/or alerting systems and personnel whenever the postalcarrier appears to be transmitting (via the mobile station 140) from alocation different from what the route id and site code indicate. Thefollowing are examples of such reasonability tests:

-   -   (a) If a threshold number of postal carrier transmittals        disagree with the location center 142 estimate by a        predetermined distance (likely dependent upon area type), then        tag these particular transmittals as problematic and mark all        transmittals from the mobile station 140 as suspect for        “distance” inaccuracies.    -   (b) If there is less than a threshold amount of time between        certain postal carrier transmittals, then tag these particular        transmittals as problematic and mark all transmittals from the        mobile station 140 as suspect for “time” inaccuracies.    -   (c) If an expected statistical deviation between a sampling of        the postal carrier transmittals and the location estimates from        the location center 142 vary by more than a threshold amount,        then tag these particular transmittals as problematic and mark        all transmittals from the mobile station 140 as suspect for        “statistical” inaccuracies.    -   (d) If an expected statistical deviation between a sampling of        the times of the postal carrier transmittals and an expected        timing between these transmittals vary by more than a threshold        amount, then tag these particular transmittals as problematic        and mark all transmittals from the mobile station 140 as suspect        for “statistical” inaccuracies.

(27.3.4) When suspect or problematic mobile station location informationis detected (e.g., incorrect site code) in step (27.3.3), the datacollection system may perform any of the following actions:

-   -   (a) Alert the postal carrier of problematic and/or suspected        inaccuracies in real time, after a certain number of        transmittals or at a later time. Note that such alerts as well        as positive feedback at the end of the postal carrier's route        (or segments thereof) may be advantageous in that it likely        inhibits the postal carrier from experimenting with transmittals        from locations that are purposefully inaccurate, but at the same        time provides sufficiently timely feedback to encourage a        conscientious postal carrier.    -   (b) Alert the Postal Service of perceived discrepancies in the        mobile station 140 transmittals by the postal carrier.    -   (c) Dispatch location center technicians to the area to transmit        duplicate signals.

(27.3.5) If the transmittal(s) from the mobile station 140 are notsuspect, then the data collection system communicates with the locationcenter 142 for requesting that each location received from the mobilestation 140 be stored with its corresponding retrieved location(obtained in step (d2)) as a verified location value in the LocationData Base (not shown). Alternatively, if the transmittals from themobile station 140 are suspect, then the data collection system maycommunicate with the location center 142 for requesting that at leastsome of the location data from the mobile station 140 be discarded.

Note that a similar or identical procedure to the steps immediatelyabove may be applied with other services/workers such as courierservices, delivery services, meter readers, street sweepers, and busdrivers having predetermined routes.

Additional Modules to Increase Location Hypothesis Accuracy

The following modules may be provided in various embodiments of thepresent invention, and in particular, as part of the location engine139. Further modules and description directed to the location center 142and its functionality, the location engine 139, various locationenhancing techniques, and various additional embodiments are provided inU.S. Provisional Patent Application having Ser. No. 60/044,821, filedApr. 25, 1997, by Dupray, Karr, and LeBlanc from which the presentapplication claims priority, and which is fully incorporated herein byreference.

Path Comparison Module

The Path Comparison Module implements the following strategy: theconfidence of a particular location hypothesis is be increased(decreased) if it is (not) predicting a path that lies along a knowntransportation pathway (and the speed of the target MS is sufficientlyhigh). For instance, if a time series of target MS location hypothesesfor a given FOM is predicting a path of the target MS that lies along aninterstate highway, the confidence of the currently active locationhypothesis for this FOM should, in general, be increased. Thus, at ahigh level the following steps may be performed:

-   -   (a) For each FOM having a currently active location hypothesis        in a Run-time Location Hypothesis Storage Area, determine a        recent “path” obtained from a time series of location hypotheses        for the FOM. This computation for the “path” is performed by        stringing together successive “center of area” (COA) or centroid        values determined from the most pertinent target MS location        estimate in each location hypothesis (recall that each location        hypothesis may have a plurality of target MS area estimates with        one being the most pertinent). The information is stored in, for        example, a matrix of values wherein one dimension of the matrix        identifies the FOM and the a second dimension of the matrix        represents a series of COA path values. Of course, some entries        in the matrix may be undefined.    -   (b) Compare each path obtained in (a) against known        transportation pathways in an area containing the path. A value,        path_match(i), representing to what extent the path matches any        known transportation pathway is computed. Such values are used        later in a computation for adjusting the confidence of each        corresponding currently active location hypothesis.        Velocity/Acceleration Calculation Module

The Velocity/Acceleration Calculation Module computes velocity and/oracceleration estimates for the target MS using currently active locationhypotheses and previous location hypothesis estimates of the target MS.In one embodiment, for each FOM having a currently active locationhypothesis (with positive confidences) and a sufficient number ofprevious (reasonably recent) target MS location hypotheses, a velocityand/or acceleration may be calculated. In an alternative embodiment,such a velocity and/or acceleration may be calculated using thecurrently active location hypotheses and one or more recent “mostlikely” locations of the target MS output by the Location Center. If theestimated velocity and/or acceleration corresponding to a currentlyactive location hypothesis is reasonable for the region, then itsconfidence value is incremented; if not, then its confidence isdecremented. The algorithm may be summarized as follows:

-   -   (a) Approximate speed and/or acceleration estimates for        currently active target MS location hypotheses may be provided        using path information related to the currently active location        hypotheses and previous target MS location estimates in a manner        similar to the description of the Path Comparison Module.        Accordingly, a single confidence adjustment number may be        determined for each currently active location hypothesis for        indicating the extent to which its corresponding velocity and/or        acceleration calculations are reasonable for its particular        target MS location estimate. This calculation is performed by        retrieving information from an Area Characteristics Data Base.        Since each location hypothesis includes timestamp data        indicating when the MS location signals were received from the        target MS, the velocity and/or acceleration associated with a        path for a currently active location hypothesis can be        straightforwardly approximated. Accordingly, a confidence        adjustment value, vel_ok(i), indicating a likelihood that the        velocity calculated for the i^(th) currently active location        hypothesis (having adequate corresponding path information) may        be appropriate for the environmental characteristics of the        location hypothesis' target MS location estimate. Thus, if the        target MS location estimate includes a portion of an interstate        highway, then an appropriate velocity might correspond to a        speed of up to 100 miles per hour, whereas if the target MS        location estimate includes only rural dirt roads and tomato        patches, then a likely speed might be no more than 30 miles per        hour with an maximum speed of 60 miles per hour (assuming        favorable environmental characteristics such as weather). Note        that a list of such environmental characteristics may include        such factors as: area type, time of day, season. Further note        that more unpredictable environmental characteristics such as        traffic flow patterns, weather (e.g., clear, raining, snowing,        etc.) may also be included, values for these latter        characteristics coming from an Environmental Data Base which        receives and maintains information on such unpredictable        characteristics. Also note that a similar confidence adjustment        value, acc_ok(i), may be provided for currently active location        hypotheses, wherein the confidence adjustment is related to the        appropriateness of the acceleration estimate of the target MS.        Attribute Comparison Module

The Attribute Comparison Module compares attribute values for locationhypotheses generated from different FOMs, and determines if theconfidence of certain of the currently active location hypotheses shouldbe increased due to a similarity in related values for the attribute.That is, for an attribute A, an attribute value for A derived from a setS_(FOM[1]) of one or more location hypotheses generated by one FOM,FOM[1], is compared with another attribute value for A derived from aset S_(FOM2) of one or more location hypotheses generated by a differentFOM, FOM[2] for determining if these attribute values cluster (i.e., aresufficiently close to one another) so that a currently active locationhypothesis in S_(FOM[1]) and a currently active location hypothesis inS_(FOM2) should have their confidences increased. For example, theattribute may be a “target MS path data” attribute, wherein a value forthe attribute is an estimated target MS path derived from locationhypotheses generated by a fixed FOM over some (recent) time period.Alternatively, the attribute might be, for example, one of a velocityand/or acceleration, wherein a value for the attribute is a velocityand/or acceleration derived from location hypotheses generated by afixed FOM over some (recent) time period.

In a general context, the Attribute Comparison Module operates accordingto the following premise: (37.1) for each of two or more currentlyactive location hypotheses (with positive confidences) if:

-   -   (a) each of these currently active location hypotheses, H, was        initially generated by a corresponding different FOM_(H);    -   (b) for a given MS estimate attribute and each such currently        active location hypothesis, H, there is a corresponding value        for the attribute (e.g., the attribute value might be an MS path        estimate, or alternatively an MS estimated velocity, or an MS        estimated acceleration) wherein the attribute value is derived        without using a FOM different from FOM_(H), and;    -   (c) the derived attribute values cluster sufficiently well,    -   then each of these currently active location hypotheses, H, will        have their corresponding confidences increased. That is, these        confidences will be increased by a confidence adjustment value        or delta.

Note that the phrase “cluster sufficiently well” above may have a numberof technical embodiments, including performing various cluster analysistechniques wherein any clusters (according to some statistic) mustsatisfy a system set threshold for the members of the cluster beingclose enough to one another. Further, upon determining the (any)location hypotheses satisfying (37.1), there are various techniques thatmay be used in determining a change or delta in confidences to beapplied. For example, in one embodiment, an initial default confidencedelta that may be utilized is: if “cf” denotes the confidence of such acurrently active location hypothesis satisfying (37.1), then anincreased confidence that still remains in the interval [0, 1.0] may be:cf+[(1−cf)/(1+cf)]², or, cf*[1.0+cf^(n)], n>=2, or, cf*[a constanthaving a system tuned parameter as a factor]. That is, the confidencedeltas for these examples are: [(1−cf)/(1+cf )]² (an additive delta),and, [1.0+cf^(n)] (a multiplicative delta), and a constant.Additionally, note that it is within the scope the present invention toalso provide such confidence deltas (additive deltas or multiplicativedeltas) with factors related to the number of such location hypothesesin the cluster.

Moreover, note that it is an aspect of the present invention to providean adaptive mechanism for automatically determining performanceenhancing changes in confidence adjustment values such as the confidencedeltas for the present module. That is, such changes are determined byapplying an adaptive mechanism, such as a genetic algorithm, to acollection of “system parameters” (including parameters specifyingconfidence adjustment values as well as system parameters) in order toenhance performance of the present invention. More particularly, such anadaptive mechanism may repeatedly perform the following steps:

-   -   (a) modify such system parameters;    -   (b) consequently activate an instantiation of the Location        Center (having the modified system parameters) to process, as        input, a series of MS signal location data that has been        archived together with data corresponding to a verified MS        location from which signal location data was transmitted (e.g.,        such data as is stored in a Data Base); and    -   (c) then determine if the modifications to the system parameters        enhanced Location Center performance in comparison to previous        performances.

Assuming this module adjusts confidences of currently active locationhypotheses according to one or more of the attributes: target MS pathdata, target MS velocity, and target MS acceleration, the computationfor this module may be summarized in the following steps:

-   -   (a) Determine if any of the currently active location hypotheses        satisfy the premise (37.1) for the attribute. Note that in        making this determination, average distances and average        standard deviations for the paths (velocities and/or        accelerations) corresponding to currently active location        hypotheses may be computed.    -   (b) For each currently active location hypothesis (wherein “i”        uniquely identifies the location hypothesis) selected to have        its confidence increased, a confidence adjustment value,        path_similar(i) (alternatively, velocity_similar(i) and/or        acceleration_similar(i) ), is computed indicating the extent to        which the attribute value matches another attribute value being        predicted by another FOM.

Note that such confidence adjustment values are used later in thecalculation of an aggregate confidence adjustment to particularcurrently active location hypotheses.

Extrapolation Module

The Extrapolation Module works on the following premise: if for acurrently active location hypothesis there is sufficient previousrelated information regarding estimates of the target MS (e.g., from thesame FOM or from using a “most likely” previous target MS estimateoutput by the Location Center), then an extrapolation may be performedfor predicting future target MS locations that can be compared with newlocation hypotheses. Note that interpolation routines (e.g.,conventional algorithms such as Lagrange or Newton polynomials) may beused to determine an equation that approximates a target MS pathcorresponding to a currently active location hypothesis. Subsequently,such an extrapolation equation may be used to compute a future target MSlocation. For further information regarding such interpolation schemes,the following reference is incorporated herein by reference: Mathews,1992, Numerical methods for mathematics, science, and engineering.Englewood Cliffs, N.J.: Prentice Hall.

Accordingly, if a new currently active location hypothesis is received,then the target MS location estimate of the new location hypothesis maybe compared with the predicted location. Consequently, a confidenceadjustment value can be determined according to how well if the locationhypothesis “i”. That is, this confidence adjustment value will be largeras the new MS estimate and the predicted estimate become closertogether.

Note that in one embodiment of the present invention, such predictionsare based solely on previous target MS location estimates output byLocation Center. Thus, in such an embodiment, substantially everycurrently active location hypothesis can be provided with a confidenceadjustment value by this module once a sufficient number of previoustarget MS location estimates have been output. Accordingly, a value,extrapolation_chk(i), that represents how accurately the new currentlyactive location hypothesis (identified here by “i”) matches thepredicted location is determined.

Analytical Reasoner Controller

Given one or more currently active location hypotheses for the sametarget MS input to a controller (denoted the Analytical ReasonerController herein), this controller activates, for each such inputlocation hypothesis, the other submodules (denoted hereinafter as“adjustment submodules”) with this location hypothesis. Subsequently,the Analytical Reasoner Controller receives an output confidenceadjustment value computed by each adjustment submodule for adjusting theconfidence of this location hypothesis. Note that each adjustmentsubmodule determines:

-   -   (a) whether the adjustment submodule may appropriately compute a        confidence adjustment value for the location hypothesis supplied        by the controller. (For example, in some cases there may not be        a sufficient number of location hypotheses in a time series from        a fixed FOM.);    -   (b) if appropriate, then the adjustment submodule computes a        non-zero confidence adjustment value that is returned to the        Analytical Reasoner Controller.

Subsequently, the controller uses the output from the adjustmentsubmodules to compute an aggregate confidence adjustment for thecorresponding location hypothesis. In one particular embodiment of thepresent invention, values for the eight types of confidence adjustmentvalues (described in sections above) are output to the presentcontroller for computing an aggregate confidence adjustment value foradjusting the confidence of the currently active location hypothesispresently being analyzed. As an example of how such confidenceadjustment values may be utilized, assuming a currently active locationhypothesis is identified by “i”, the outputs from the above describedadjustment submodules may be more fully described as:

-   -   path_match(i) 1 if there are sufficient previous (and recent)        location hypotheses for the same target MS as “i” that have been        generated by the same FOM that generated “i”, and, the target MS        location estimates provided by the location hypothesis “i” and        the previous location hypotheses follow a known transportation        pathway. 0 otherwise.    -   vel_ok(i) 1 if the velocity calculated for the i^(th) currently        active location hypothesis (assuming adequate corresponding path        information) is typical for the area (and the current        environmental characteristics) of this location hypothesis'        target MS location estimate; 0.2 if the velocity calculated for        the i^(th) currently active location hypothesis is near a        maximum for the area (and the current environmental        characteristics) of this location hypothesis' target MS location        estimate; 0 if the velocity calculated is above the maximum.    -   acc_ok(i) 1 if the acceleration calculated for the i^(th)        currently active location hypothesis (assuming adequate        corresponding path information) is typical for the area (and the        current environmental characteristics) of this location        hypothesis' target MS location estimate; 0.2 if the acceleration        calculated for the i^(th) currently active location hypothesis        is near a maximum for the area (and the current environmental        characteristics) of this location hypothesis' target MS location        estimate; 0 if the acceleration calculated is above the maximum.    -   similar_path(i) 1 if the location hypothesis “i” satisfies        (37.1) for the target MS path data attribute; 0 otherwise.    -   velocity_similar(i) 1 if the location hypothesis “i” satisfies        (37.1) for the target MS velocity attribute; 0 otherwise.    -   acceleration_similar(i) 1 if the location hypothesis “i”        satisfies (37.1) for the target MS acceleration attribute; 0        otherwise.    -   extrapolation_chk(i) 1 if the location hypothesis “i” is “near”        a previously predicted MS location for the target MS; 0        otherwise.

Additionally, for each of the above confidence adjustments, there is acorresponding Location Center system settable parameter whose value maybe determined by repeated activation of an Adaptation Engine.Accordingly, for each of the confidence adjustment types, T, above,there is a corresponding system settable parameter, “alpha_T”, that istunable by the Adaptation Engine. Accordingly, the following high levelprogram segment illustrates the aggregate confidence adjustment valuecomputed by the Analytical Reasoner Controller.

target_MS_loc_hyps←get all currently active location hypotheses, H,identifying the present target;   for each currently active locationhypothesis, hyp(i),   from target_MS_loc_hyps do   {      for each ofthe confidence adjustment submodules, CA, do       activate CA withhyp(i) as input; /* now compute the aggregate confidence adjustmentusing the  output from the confidence adjustment submodules. */    aggregate_adjustment(i) <-- alpha_path_match *     path_match(i)        + alpha_velocity * vel_ok(i)         + alpha_path_similar *path_similar(i)         + alpha_velocity_similar * velocity_similar(i)        + alpha_acceleration_similar* acceleration_similar(i)         +alpha_extrapolation * extrapolation_chk(i);     hyp(i).confidence <--hyp(i).confidence +     aggregate_adjustment(i);   }Wireless Location Applications

After having determined wireless location from a base technologyperspective, several applications are detailed below, which provide theresults of the location information to a variety of users in variouschannels and presentation schemes, for a number of useful reasons andunder various conditions. The following applications are addressed: (1.)providing wireless location to the originator or another, using eitherthe digital air interface voice channel or a wireline channel, and anautomatic call distributor; (2.) providing wireless location to theoriginator, or another, using either the digital air interface voicechannel or a wireline channel, and a hunt group associated with thecentral office or a PBS group; (3.) providing wireless location to theoriginator or another, using either the digital air interface textpaging, or short message service communications channel; (4.) providingwireless location to the originator or another, using the Internet, andin one embodiment, using netcasting or “Push” technology; (5.) selectivegroup, multicast individualized directions with optional Conferencing;(6.) rental car inventory control and dispatch; (7.) vocalizeddirections and tracking; (8.) wireless location and courtruling/criminal incarceration validation; (9.) flexible delivery ofwireless location information to public safety answering points; (10.)trigger-based inventory and tracking; (11.) group, e.g., family, safetyand conditional notification; (12.) wireless location-basedretail/merchandising services; ( 13.) location-based home/office/vehiclesecurity management; (13.) infrastructure-supported wireless locationusing hand-actuated directional finding; (14.) infrastructure-supportedintelligent traffic and highway management; (15.) Parametric-drivenintelligent agent-based location services. Each of these wirelesslocation applications is discussed in detail below.

Providing Wireless Location using an ACD Application

Referring to FIG. 36, a user (the initiating caller) desiring thelocation of a target mobile station 140 a, such as a user at a telephonestation 162 which is in communication with a tandem switch 489 or a userof an mobile station 140 b, or any other telephone station user, such asa computer program, dials a publicly dialable telephone number whichterminates on the automatic call distributor 546 (ACD), associated withthe location center 142. If the caller originated the call from a mobilestation 140 b, then the call is processed via a base station 122 b to amobile switch center 112 a. The mobile switch center 112 a recognizesthat the call is to be routed to the PSTN 124 via an interoffice trunkinterface 600. The PSTN 124 completes the call to the ACD 546, via atrunk group interface 500. Note that the initiating caller could accessthe ACD 546 in any number of ways, including various Inter-LATA Carriers492, via the public switched telephone network (PSTN) 124. The ACD 546includes a plurality of telephone network interface cards 508 whichprovide telephony channel associated signaling functions, such as pulsedialing and detection, automatic number identification, winking, flash,off-hook voice synthesized answer, dual tone multi frequency (DTMF)detection, system intercept tones (i.e., busy, no-answer,out-of-service), disconnected, call progress, answer machine detection,text-to-speech and automatic speech recognition. Note that some of thesefunctions may be implemented with associated digital signal processingcards connected to the network cards via an internal bus system. Anassigned telephone network interface card 508 detects the incoming call,provides an off-hook (answer signal) to the calling party, then providesa text to speech (TTS) message, via an assigned text-to-speech card 512indicating the nature of the call to the user, collects the automaticnumber identification information if available (or optionally promptsthe caller for this information), then proceeds to collect the mobileidentification number (MIN) to be located. MIN collection, which isprovided by the initiating caller through keypad signaling tones, can beachieved in several methods. In one case the network card 508 canrequest a TTS message via text-to-speech card 512, which prompts theinitiator to key in the MIN number by keypad DTMF signals, or anautomatic speech recognition system can be used to collect the MINdigits. After the MIN digits have been collected, a location requestmessage is sent to a location application 146. The location application146, in concert with location application interface 14 (moreparticularly, L-API-Loc 135, see FIG. 36), in the location system 142,is in communication with the location engine 139. Note that the locationengine 139 includes the signal processing subsystem 20, and one or morelocation estimate modules, i.e., DA module 10, TOA/TDOA module 8 or HBSmodule 6. The location engine 139 initiates a series of messages, usingthe location application programming interface (L-API-MSC 136) to themobile switch center 112 a. The location application programminginterface 136 then communicates with one or more mobile switch centers112 b, to determine whether or not the mobile station 140 a to belocated can be located. Conditions affecting the locateability of themobile station 140 a include, for example: the mobile station 140 abeing powered off, the mobile station 140 a not being in communicationrange, the mobile station 140 a roaming state not being known, themobile station 140 a not being provisioned for service, and relatedconditions. If the mobile station 140 a cannot be located then anappropriate error response message is provided to the initiating caller,via e-mail, using the web server 464 in communications with the Internet468 via an Internet access channel 472 or alternatively the errorresponse message may be sent to a text to speech card 512, which is incommunications with the initiating caller via the telephone interfacecard 508 and the ACD 546, which is in communication via telephonyinterface circuits 500 to the PSTN 124.

Note that in cases where rendering location estimate information isrequired on the Internet, the web server 464 can include the provisionof a digital certificate key, thus enabling a secure, encryptedcommunication channel between the location web server 464 and thereceiving client. One such digital encryption key capability is a webserver provided by Netscape Communications, Inc. and a digitalcertificate key provided by Verisign, Inc. both located in the state ofCalifornia, U.S.A.

The PSTN 124 completes routing of the response message to the initiatingcaller via routine telephony principles, as one skilled in the art willunderstand. Otherwise the mobile station 140 a is located using methodsdescribed in greater detail elsewhere herein. At a high level, themobile switch center 112 a is in communication with the appropriate basestations 122, and provides the location system 142 with the necessarysignal and data results to enable a location estimation to be performedby the location engine 139. Once the location has been determined by thelocation engine 139 in terms of Latitude, Longitude and optionallyheight if known (in the form of a text string), the result is providedby to the initiator by inputting the location text string to atext-to-speech card 512, which in turn is in communication with theassigned telephone interface card 508, via the automatic controldistributor 546, for completing the communication path and providing thelocation response back to the initiating user via the telephoneinterface 500 to the PSTN 124, and from the PSTN 124 to the initiatinguser.

Alternatively the location results from the location application 146(e.g., FIGS. 37 and 38) could be provided to the initiating caller orInternet user via a web server 464 in communication with the Internet468, via an Internet access channel 472 and a firewall 474 (e.g., FIG.36). In another embodiment, the location results determined by thelocation application 146 may be presented in terms of street addresses,neighborhood areas, building names, and related means familiar to humanusers. The alternative location result can be achieved by previouslystoring a relationship between location descriptors familiar to humansand Latitude and Longitude range values in a map database 538 (FIG. 36).During the location request, the location application 146 accesses themap database 538, providing it with the Latitude and Longitudeinformation in the form of a primary key which is then used to retrievethe location descriptor familiar to humans. Note that to those skilledin the art, the map database 538 and associated messaging between themap database 538 and the location application 146 can be implemented inany number of techniques. A straightforward approach includes defining alogical and physical data model using a relational database and designerenvironment, such as “ORACLE 2000” for the design and development, usinga relational database, such as the “ORACLE 7.3” database.

In an alternative embodiment, the location application 146 may beinternal to the location system 142 (e.g. FIG. 37), as one skilled inthe art will understand.

Providing Wireless Location via Hunt Groups Application

Referring to FIGS. 37 and 38, a user—the initiating caller, such as amobile station 140 a desiring the location of a mobile station 140,signals to the primary base station 122 g, in connection with the mobileswitch center 112 via transport facilities 176. The mobile switch center112 is connected to the PSTN 124, via interoffice trunks 600. Theinitiating user dials a publicly dialable telephone number which is thenrouted through an end office 496, to a telephone interface card 508, viaa telephone hunt group 500. The hunt group 500 provides a telephonyconnection to the interface card 247 associated with the location-system142. The hunt group trunk interface 500 is provided from an end officetelephone switch 496. Note that the initiating caller could access thetelephony interface card 508, via hunt group trunk interface 500 in anynumber of ways, including an InterLATA Carrier 492, via the publicswitched telephone network (PSTN) 124. The hunt group trunk interface500 is in communication with a plurality of telephone interface cards508. The interface cards 508 provide telephony channel associatedsignaling functions, such as pulse dialing and detection, automaticnumber identification, winking, flash, off-hook voice synthesizedanswer, dual tone multi frequency (DTMF) detection, system intercepttones (i.e., busy, no-answer, out-of-service), disconnected, callprogress, answer machine detection, text-to-speech and automatic speechrecognition. An assigned network interface card 508 detects the incomingcall, provides an off-hook (answer signal) to the calling party, thenprovides a text to speech (TTS) message indicating the nature of thecall to the user, collects the automatic number identificationinformation if available (or optionally prompts the caller for thisinformation), then proceeds to collect the mobile identification number(MIN) to be located. MIN collection can be achieved in several methods.In one case the network card 508 can request a TTS message, generated bya voice synthesizer or text to speech card 512, which prompts theinitiator to key in the MIN number by keypad tone signals, or anautomatic speech recognition system can be used to collect the MINdigits. After the MIN digits have been collected, a location requestmessage is sent to an application 146 in the location system 142. Theapplication 146 in location system 142 initiates a series of messages tothe mobile switch center 112, and optionally to the home locationregister 460, to determine whether or not the mobile station 140 to belocated can be located. If the mobile station 140 cannot be located thenan appropriate error response message is provided to the initiatingcaller, via e-mail, test to speech card 512, web server 464 incommunications with the public Internet 468, or similar means.Alternatively the last known location can be provided, along with thetime and date stamp of the last location, including an explanation thatthe current location is not attainable. Otherwise the mobile station 140is located using methods described in greater detail elsewhere in thispatent. At a high level, the mobile switch center 112 is incommunication with the appropriate base stations 122 g and 122 h, andprovides the location system 142 with the necessary signal and dataresults to enable a location estimation to be performed by the locationsystem 142. Once the location has been determined by the location system142 in terms of Latitude, Longitude and optionally height if known (inthe form of a text string), the result is provided back to the initiatorby inputting the location text string to a text-to-speech card 512, incommunication with the assigned telephone interface card 508. Theinterface card 508 then provides the audible, synthesized messagecontaining the location estimate to the initiating caller. Alternativelythe location results could be provided to the initiating caller via aweb server 464 in communication with the Public Internet 468, usingstandard client request-response Internet protocols and technology.location system 142 access to a geographical information system or othermapping system could also be used to further enhance the userunderstanding of the location on a map or similar graphical display.

Providing Wireless Location Via Text Paging Application

Referring to FIG. 38, a user (the initiating caller) desiring thelocation of an mobile station 140, such as a wireless user using mobilestation 140 who has text paging service provisioned, dials a publiclydialable telephone number, carried to the PSTN 124 which terminates onan end office 496 based hunt group interface 500, which in turn is incommunication with the location system 142. The mobile switch center112, local tandem 317 and interLATA Carrier tandem 362 are incommunication with the PSTN 124, as those skilled in the art willunderstand. Note that the initiating caller could also be a wirelineuser with an ordinary telephone station 162 in communication with alocal tandem 489, connected to the PSTN 124. The initiating locationrequest user could access the telephony interface cards 512 via the huntgroup 500. In other embodiments, including various Inter-LATA Carriers492, via the public switched telephone network (PSTN) 124. The huntgroup interface 500 is in communication with a plurality of telephonenetwork interface cards 512, which are in communication with thelocation application 146. The telephone interface cards 512 providetelephony channel associated signaling functions, such as pulse dialingand detection, automatic number identification, winking, flash, off-hookvoice synthesized answer, dual tone multi frequency (DTMF) detection,system intercept tones (i.e., busy, no-answer, out-of-service),disconnected, call progress, answer machine detection, text-to-speechand automatic speech recognition. Note that some of these functions maybe implemented with associated digital signal processing cards connectedto the network cards via an internal bus system. An assigned telephonyinterface card 508 detects the incoming call, provides an off-hook(answer signal) to the calling party, then provides, if appropriate, atext to speech (TTS) message indicating the nature of the call to theuser, collects the automatic number identification information ifavailable (or optionally prompts the caller for this information), thenproceeds to collect the mobile identification number (MIN) to be locatedby sending a location request message to an application 146 in thelocation system 142. The mobile station MIN collection, provided throughthe communications channel established, is sent by the initiating callerthrough keypad signaling tones. This MIN collection process can beachieved in several methods. In one case the telephony interface card512 can request a text-to-speech message, generated by a text-to-speechcard 512, which prompts the initiator to key in the MIN number by keypadtone signals. In another case an automatic speech recognition system canbe used to collect the MIN digits. In either case, after the MIN digitshave been collected, a location request message is sent to the locationsystem 142. The location system 142 initiates a series of messages tothe mobile switch center 112, via the location applications programminginterface (L-API-MSC 136), and optionally to the home location register460, to determine whether or not the mobile station 140 to be locatedcan in fact be located. Alternatively the last known location can beprovided, along with the time and date stamp of the last location,including an explanation that the current location is not attainable.Conditions regarding the locateability of a mobile station include, forexample: mobile station 140 powered off, mobile station not incommunication range, mobile station roaming state not known, mobilestation 140 not provisioned for service, and related conditions. If themobile station 140 cannot be located then an appropriate error responsemessage is provided to the initiating caller, via the service node (SN)107 for short messaging service (SMS). The service node is incommunication with the location system 142 using a common text paginginterface 108. The service node 107 accepts the location text pagingmessage from the location system 142 and communicates a request to pagethe initiating caller via a typical signaling system 7 link for pagingpurposes, to the mobile switch center 112. The mobile switch center 112forwards the location text page information to the initiating caller viathe appropriate base stations, to the initiating mobile station caller.Otherwise the mobile station 140 is located using methods described ingreater detail elsewhere in this patent. At a high level, the mobileswitch center 112 is in communication with the appropriate basestations, and provides the location system 142 with the necessary signaland data results to enable a location estimation to be performed by thelocation system 142. Once the location has been determined by thelocation system 142 in terms of Latitude, Longitude and optionallyheight if known (in the form of a text string). The location result isprovided to the initiator by inputting the location text string to theservice node 107 for short messaging service (SMS). The service node 107is in communication with the location system 142 using a common textpaging interface 108. The service node 107 accepts the location textpaging message from the location system 142 and communicates a requestto page the initiating caller via a typical signaling system 7 link 105for paging purposes, to the mobile switch center 112. The mobile switchcenter 112 forwards the location text page information to the initiatingcaller via the appropriate-base stations 122 a or 122 b (not shown inFIG. 38), to the initiating caller, via a text-to-speech card 512, incommunication with the assigned telephone interface card 508.

Providing Wireless Location using Internet Push Technology Application

Referring to FIG. 39, a user (the initiating user) desiring the locationof an mobile station 140, who has a push technology tuner 484 associatedwith the user's client workstation 482, selects the location channel inthe area, and further specifies the mobile station(s) 140 to be located,with what frequency should the location estimate be provided, and otherrelated parameters, such as billing information. The user's clientworkstation 482 is in communication with the Internet, optionally via anencrypted communications channel (e.g. channel 490) using, for example,Netscape's SSL 3 encryption/decryption technology. A push transmitter472, connected to the Internet 468 via a web server 464, detects theclient workstation 482 user's request. The transmitter 472 requestslocation update information for specified mobile identification numbersthrough a firewall 474 and a publisher 478, in communication with alocation channel application 429 in the location system 142. Thelocation system 142 initiates location requests for all mobile stationmobile identification numbers for which location information has beensubscribed to, then provides the location results to the locationchannel application 429.

The location system 142 initiates a series of messages to the mobileswitch center 112, via the location applications programming interface(L-API-MSC 136), and optionally to the home location register (HLR) 460,to determine whether or not the mobile station 140 or others, to belocated can in fact be located. Alternatively the last known locationcan be provided, along with the time and date stamp of the lastlocation, including an explanation that current location is notattainable. Conditions regarding the locateability of a mobile station140 include, for example: mobile station 140 powered off, mobile stationnot in communication range, mobile station 140 roaming state not known,mobile station 140 not provisioned for service, and related conditions.If the mobile station 140 cannot be located then an appropriate errorresponse message is provided to the initiating client workstation 482,via the push technology components location channel application 429,publisher 478, firewall 474, transmitter 472, web server 464, publicInternet 468, to the client workstation 482. A similar communicationmechanism is used to provide the client's workstation 482 with attainedlocation information.

Note that the location channel 429 could in fact provide a collection ofmobile station 140 mobile identification numbers for location purposesthat are grouped by a particular market and/or customer organizationsegment. for example, location channel number 1 could provide enhancedwireless 9-1-1 service to specific public safety answering points,channel number 2 could provide periodic wireless location information ofa fleet of taxi cabs belonging to a particular company, to theirdispatch operator, channel 3 could provide wireless location to acontrol center of a military organization, channel 4 could providewireless location information of vehicles carrying hazardous materials,to a control center, and so forth.

The location channel application 429 provides the location results tothe publisher 478, which provides a method of adding the new locationresults to the transmitter 472, via firewall 474. The firewall 474,provides protection services between certain systems and the Internet468, such as preventing malicious users from accessing criticalcomputing systems.

Selective Group, Multicast, Individualized Directions ConferencingApplication

The group multicast help, with individualized directions, is anapplication wherein for members of a group that are authorized andnearest a distressed caller, these members are given text paging messageinstructions on how to drive or navigate, to reach the initiatingdistressed caller. Alternatively optional voice synthesis technologycould be used to aid one or more members to have spoken instructiongiving directions and/or instructions for each member, to help themreach the distressed caller.

Referring to FIG. 40, an individual having a mobile station 140 desiresto make a distress call for help, or for some other reason. Thedistressed caller with mobile station 140 dials a special telephonenumber, received by base station 122, which then sends the originatingcall setup request to the mobile switch center 112. The mobile switchcenter 112 routes the originating call through the PSTN 124 to anautomatic call distributor (ACD) 546. The ACD 546 selects an availabletelephony interface circuit 508, which answers the call and providesintroductory information to the caller, such as a greeting message,progress of service, etc., using a voice synthesizer circuit card 512.Note that circuits 508 and 512 may be combined as voice response units.The telephony interface circuit 508 collects the automatic numberidentification information if available in the call setup message oroptionally prompts the caller for this information. This MIN collectionprocess can be achieved in several methods. In one case the networktelephony interface card 508 can request a TTS (text to speech) message,generated by a voice synthesizer card 512, which prompts the initiatorto key in their MIN number by keypad tone signals. In another case anautomatic speech recognition system can be used to collect the MINdigits. In either case after the MIN digits have been collected, alocation request message is sent to the location system 142. Thelocation system or location center (LC) 142 initiates a series ofmessages to the mobile switch center 112, via the location applicationsprogramming interface (L-API-MSC 136), to determine whether or not themobile station 140 to be located can in fact be located. If the mobilestation 140 cannot be located then an appropriate error response messageis provided to the initiating caller. Otherwise the LC 142 determinesthe caller's location via methods discussed elsewhere in this patent.While this event is proceeding an application in the LS 142 referencesthe initiating caller's location subscriber profile database (not shown)to determine if the caller allows others to locate him or her, andspecifically which individuals are allowed to be informed of thecaller's location.

Assuming the caller allows location information to be sent out to aselect group, then the list of member's mobile station identificationnumbers (MIN)s are extracted from the profile database, and anapplication in the LC 142 initiates a series of messages to the mobileswitch center 112, via the location applications programming interface(L-API-MSC 136), to determine the locations of each of the users' mobilestation mobile identification numbers associated with the member list.Regarding those mobile station mobile identification numbers nearest thedistress caller, each member's mobile station is dialed via a controlmessage sent from an application in the LC 142 to the telephonyinterface card 508. A voice synthesizer card 512 or text to speechcircuit is also patched in the calling circuit path, to announce thepurpose of the automated call to each member. The ACD 546 initiates thecall request to each member via the PSTN 124, which connects to themobile switch center 112, that ultimately rings the member mobilestation 140 and 148 via base stations 122. An application in the LC 142identifies a start and finish location destination location for amember, based on his/her current location as being the start location,and the finish location being the distress caller's location at mobilestation MIN. The application in the LC 142 initiates a http or similarInternet compatible protocol universal resource locator (URL) requestvia the web server/client 530 to the public Internet 468, whichterminates on a maps, directions web server 534. One such URL known tothe authors is Lucent Technologies' http://www.mapsOnUs.com, which isprovided for public use. The map/directions server 534 queries the mapbase 536 via a directions algorithm, and returns to the initiating httprequest, the location web server 530, with a list of instructions toenable a user to navigate between a start location and end location.Referring to FIG. 41, the information shown in the columns labeled “Turn#”, “Directions”, “And Go”, and/or “Total Miles”, can then be parsedfrom the http response information. Referring now to FIG. 40, thisinformation can then be sent as a short text message, to the relevantmobile station 148 or 140 via the service node 107, using interface 105to the mobile switch center 112, and relevant base stations 122,assuming each member mobile station has short message serviceprovisioned. If this is not the case, the service node 107 will informthe application within the LS 142, which then initiates an alternativemethod of sending the start-finish location navigation instructionsinformation via an appropriate voice synthesizer card 512 and associatedtelephony interface card 508. The interface card 508 initiates anautomated call to each appropriate member's mobile station 148 and 140,via the telephony path including components ACD 546 in communicationwith the PSTN 124, which is in communication with the mobile switchcenter 112. The mobile switch center 112 completes the routing of theautomated call to the appropriate mobile station 140 using base stations122. The above process is repeated for each nearby member's mobilestation, thus allowing all nearby members to be notified that thedistressed caller needs help, with navigation instructions to eachmember, which enables the member to reach the distressed caller.Variations of this application include putting each relevant party incommunication with each other via a conference call capability in theACD 546, with or without providing location information and/orstart-finish navigation instructions.

Rental Car Inventory, Tracking and Control Application

An application in the location system utilizes periodic wirelesslocation of appropriate rental cars, control circuits and controlcommunications within the rental car, and secured transactions acrossthe Internet, or similar means, in order to provide various tracking andcontrol functions. Such functions allow rental car agencies to remotelycontrol and operate their rental cars in order to reduce operating costssuch as storage and maintenance, as well as provide additionalconveniences and services to rental car agency customers.

Referring to FIG. 42, a vehicle 578 containing various sensors andactuators (not shown) used to, for example, lock and unlock car doors,sense door position, keypad depressions, sense the condition of theengine and various subsystems, such as brakes, electrical subsystems,sense the amount of various fluid levels, etc., is in communication witha vehicle-based local area network 572, which is in turn connected to amobile station 140 containing asynchronous data communicationscapability. The vehicle-based local area network may optionally containa computer (not shown) for control and interfacing functions. The mobilestation 140 is always in communication, using the radio air interfacewith at least one base station 122 g, and possibly other base stations122 h. The base stations 122 g and 122 h are in communication with themobile switch center 112 via transport facilities 176. The mobile switchcenter 112 is in communication with the location system 142 and thepublic switched telephone network 124 via interoffice trunks 600. Inaddition the mobile switch center 112 is also in communication with thelocation system 142 via the location system—mobile switch centerphysical interface 178. The physical interface provides two-wayconnections to the location applications programming interface (i.e.,L-API-MSC 136), which is in communication with a location engine 139,which performs wireless location estimations for the mobile station,which is permanently mounted in the vehicle 578. The location engine 139represents key components within the location system 142 which togethercomprise the capability to perform wireless location estimations. Therental car location application 146 is in communications with thelocation engine 139 for purposes of initiating wireless locationrequests regarding the mobile station 140, as well as for receivingwireless location responses from the location engine 139. Theapplication 146 is in communications with the automatic call distributor546 for purposes of initiating and receiving telephone calls to and fromthe public switch telephone network 124, via hunt group interface 500.As one skilled in the art will appreciate, other interfaces (not shown)beyond hunt groups 500, can alternatively be used, such as ISDNinterface circuits, T-carrier and the like. The application 146 is incommunication with a web server and client 464, which in turn is incommunication with the Internet 468 via an Internet access interface472. As those in the art will understand, an Internet access interfaceis typically provided by an Internet service provider, also there areother methods which could be used to complete the Internet connection.The rental car agency contains a workstation or personal computer 582with an Internet access interface 472 to the Internet 468. Theapplication 146 requests of the location engine 139 to perform alocation request periodically regarding the mobile station 140, with thelocation response information provided the web server and client, 464.For each rental car or vehicle containing a mobile station 140, thelocation, as well as various information about the rental car or vehiclecan be ascertained via the above described infrastructure.

911 Application with Wireless Location of the Caller Reporting anIncident

An application in the location system operates in conjunction with anapplication in each public safety answering point (PSAP) that togetherprovides various call handling functions to enable the PSAP to performits work load efficiently and effectively toward unique emergency eventsunique to a given location. The application pair measures the number ofemergency 9-1-1 wireless calls originating from a particulargeographical area or location. Upon exceeding a provisional thresholdvalue “X”, the application pair traps the next incoming call from thesame location and provides a call screening function via a playannouncement and collect digits activity. This activity alerts theoriginating caller that if their call relates to an incident at aparticular location, then they are the “X+1 th” caller who has alreadynotified the PSAP, and that no further caller discussion is required.However, if the caller's intent does not relate to the incidentdescribed above, then the caller is requested to press or say “one”, orsome similar keypad number, which then is collected and causes thecaller to be re-routed to the next available PSAP call taker.Alternatively if the originating caller does not respond within a shorttime period, then the call is also re-routed to the next available PSAPcall taker. The voice announcement may either be synthesized by atext-to-speech card, or an PSAP operator may store a voice message whichdescribes the incident at the above-referenced location.

1. A method for locating a wireless mobile station, comprising:receiving first data related to wireless signals communicated between aparticular mobile station and at least a first network of a plurality ofcommercial mobile service provider networks, wherein for each saidnetwork, there are a plurality of base stations for at least one oftransmitting and receiving wireless signals with a correspondingplurality of mobile stations registered with the network, and whereinsaid particular mobile station is registered with said first network forsubscribing to a wireless service; first requesting a first locationestimate of the particular mobile station, wherein a first locationestimator provides said first location estimate of the particular mobilestation when said first location estimator is supplied with firstlocation information including data obtained using the first data, saidlocation information capable of changing with a change in a location ofthe particular mobile station; wherein when said first location estimateis one of: (a) deemed ambiguous, (b) can not be provided, (c) is notwithin a desired range of accuracy, and (d) has an extent greater thanor equal to a predetermined size, then the steps (A1) and (A2) areperformed: (A1) instructing said particular mobile station tocommunicate with a second network of the plurality of networks forsupplying second data, wherein said particular mobile station is notregistered with said second network for subscribing to a wirelessservice, and wherein said second data is obtained using wireless signalscommunicated between the particular mobile station and the secondnetwork; (A2) second requesting a second location estimate of saidparticular mobile station wherein said second location estimate isobtained using additional location information obtained at least in partfrom the second data; outputting location information for the particularmobile station, wherein said location information is dependent upon atleast one of the first and second estimates of the particular mobilestation.
 2. The method of claim 1, further including a step of obtaininginformation indicative of one of: an acceleration, and a speed of theparticular mobile station.